diff --git a/changelog_entry.yaml b/changelog_entry.yaml
index e69de29b..a48a9413 100644
--- a/changelog_entry.yaml
+++ b/changelog_entry.yaml
@@ -0,0 +1,5 @@
+- bump: minor
+  changes:
+    added:
+    - weeks_unemployed variable from CPS ASEC LKWEEKS
+    - QRF-based imputation of weeks_unemployed for Extended CPS PUF copy
diff --git a/policyengine_us_data/datasets/cps/census_cps.py b/policyengine_us_data/datasets/cps/census_cps.py
index c5941c37..00ca020e 100644
--- a/policyengine_us_data/datasets/cps/census_cps.py
+++ b/policyengine_us_data/datasets/cps/census_cps.py
@@ -261,6 +261,7 @@ class CensusCPS_2018(CensusCPS):
     "RNT_VAL",
     "SS_VAL",
     "UC_VAL",
+    "LKWEEKS",  # Weeks looking for work during the year (Census variable)
     "ANN_VAL",
     "PNSN_VAL",
     "OI_OFF",
diff --git a/policyengine_us_data/datasets/cps/cps.py b/policyengine_us_data/datasets/cps/cps.py
index b1a060e9..15e8733b 100644
--- a/policyengine_us_data/datasets/cps/cps.py
+++ b/policyengine_us_data/datasets/cps/cps.py
@@ -423,6 +423,10 @@ def add_personal_income_variables(
         cps["social_security_retirement"]
     )
     cps["unemployment_compensation"] = person.UC_VAL
+    # Weeks looking for work during the year (Census variable LKWEEKS)
+    # LKWEEKS: -1 = NIU (Not In Universe), 0 = not looking, 1-52 = weeks
+    weeks_raw = person.LKWEEKS
+    cps["weeks_unemployed"] = np.where(weeks_raw == -1, 0, weeks_raw)
     # Add pensions and annuities.
     cps_pensions = person.PNSN_VAL + person.ANN_VAL
     # Assume a constant fraction of pension income is taxable.
diff --git a/policyengine_us_data/datasets/cps/extended_cps.py b/policyengine_us_data/datasets/cps/extended_cps.py
index b9f2c81a..f96384a6 100644
--- a/policyengine_us_data/datasets/cps/extended_cps.py
+++ b/policyengine_us_data/datasets/cps/extended_cps.py
@@ -176,6 +176,12 @@ def generate(self):
         data = cps_sim.dataset.load_dataset()
         new_data = {}
 
+        # Pre-compute weeks_unemployed imputation for PUF copy
+        # Preserve relationship between UC and weeks from CPS
+        puf_weeks_unemployed = impute_weeks_unemployed_for_puf(
+            cps_sim, y_full_imputations
+        )
+
         for variable in list(data) + IMPUTED_VARIABLES:
             variable_metadata = cps_sim.tax_benefit_system.variables.get(
                 variable
@@ -206,6 +212,9 @@ def generate(self):
                 values = np.concatenate([values, values + values.max()])
             elif "_weight" in variable:
                 values = np.concatenate([values, values * 0])
+            elif variable == "weeks_unemployed":
+                # Use imputed weeks for PUF copy to preserve UC relationship
+                values = np.concatenate([values, puf_weeks_unemployed])
             else:
                 values = np.concatenate([values, values])
             new_data[variable] = {
@@ -320,6 +329,106 @@ def impute_income_variables(
     return result
 
 
+def impute_weeks_unemployed_for_puf(cps_sim, puf_imputations):
+    """
+    Impute weeks_unemployed for the PUF copy using QRF from CPS data.
+
+    Uses microimpute's Quantile Random Forest to impute weeks_unemployed
+    for PUF records based on CPS data, preserving the joint distribution
+    of weeks with UC, age, and other predictors.
+
+    This is the reverse of the income imputation (CPS → PUF instead of
+    PUF → CPS) because weeks_unemployed exists in CPS but not in PUF.
+    """
+    # Get CPS weeks
+    try:
+        cps_weeks = cps_sim.calculate("weeks_unemployed").values
+    except (ValueError, KeyError):
+        logging.warning(
+            "weeks_unemployed not available in CPS, "
+            "returning zeros for PUF copy"
+        )
+        n_persons = len(puf_imputations.index)
+        return np.zeros(n_persons)
+
+    # Predictors available in both CPS and imputed PUF data
+    WEEKS_PREDICTORS = [
+        "age",
+        "is_male",
+        "tax_unit_is_joint",
+        "is_tax_unit_head",
+        "is_tax_unit_spouse",
+        "is_tax_unit_dependent",
+    ]
+
+    # Build training data from CPS
+    X_train = cps_sim.calculate_dataframe(WEEKS_PREDICTORS)
+    X_train["weeks_unemployed"] = cps_weeks
+
+    # Add UC as predictor if available in imputations (strong predictor)
+    if "taxable_unemployment_compensation" in puf_imputations.columns:
+        cps_uc = cps_sim.calculate("unemployment_compensation").values
+        X_train["unemployment_compensation"] = cps_uc
+        WEEKS_PREDICTORS = WEEKS_PREDICTORS + ["unemployment_compensation"]
+
+    # Build test data for PUF copy
+    # Use CPS sim to get demographics (same as CPS portion)
+    X_test = cps_sim.calculate_dataframe(
+        [p for p in WEEKS_PREDICTORS if p != "unemployment_compensation"]
+    )
+
+    # Add imputed UC if available
+    if "taxable_unemployment_compensation" in puf_imputations.columns:
+        X_test["unemployment_compensation"] = puf_imputations[
+            "taxable_unemployment_compensation"
+        ].values
+
+    logging.info(
+        f"Imputing weeks_unemployed using QRF with "
+        f"predictors: {WEEKS_PREDICTORS}"
+    )
+
+    # Use QRF to impute weeks
+    qrf = QRF(
+        log_level="INFO",
+        memory_efficient=True,
+    )
+
+    # Sample training data for efficiency
+    sample_size = min(5000, len(X_train))
+    if len(X_train) > sample_size:
+        X_train_sampled = X_train.sample(n=sample_size, random_state=42)
+    else:
+        X_train_sampled = X_train
+
+    fitted_model = qrf.fit(
+        X_train=X_train_sampled,
+        predictors=WEEKS_PREDICTORS,
+        imputed_variables=["weeks_unemployed"],
+        n_jobs=1,
+    )
+
+    predictions = fitted_model.predict(X_test=X_test)
+    imputed_weeks = predictions["weeks_unemployed"].values
+
+    # Enforce constraints: 0-52 weeks, 0 if no UC
+    imputed_weeks = np.clip(imputed_weeks, 0, 52)
+    if "unemployment_compensation" in X_test.columns:
+        imputed_weeks = np.where(
+            X_test["unemployment_compensation"].values > 0,
+            imputed_weeks,
+            0,
+        )
+
+    logging.info(
+        f"Imputed weeks_unemployed for PUF: "
+        f"{(imputed_weeks > 0).sum()} with weeks > 0, "
+        f"mean = {imputed_weeks[imputed_weeks > 0].mean():.1f} weeks"
+    )
+
+    return imputed_weeks
+
+
 class ExtendedCPS_2024(ExtendedCPS):
     cps = CPS_2024_Full
     puf = PUF_2024
diff --git a/tests/test_weeks_unemployed.py b/tests/test_weeks_unemployed.py
new file mode 100644
index 00000000..2a230de2
--- /dev/null
+++ b/tests/test_weeks_unemployed.py
@@ -0,0 +1,86 @@
+"""
+Tests for weeks_unemployed variable extraction from CPS ASEC.
+
+The Census CPS ASEC uses LKWEEKS (not IPUMS's WKSUNEM1) for weeks looking for work.
+"""
+
+import numpy as np
+from pathlib import Path
+
+
+class TestWeeksUnemployed:
+    """Test suite for weeks_unemployed variable."""
+
+    def test_lkweeks_in_person_columns(self):
+        """Test that LKWEEKS is in PERSON_COLUMNS, not WKSUNEM."""
+        # Read the source file directly to check column names
+        census_cps_path = Path(__file__).parent.parent / (
+            "policyengine_us_data/datasets/cps/census_cps.py"
+        )
+        content = census_cps_path.read_text()
+
+        # Check for correct variable
+        assert '"LKWEEKS"' in content, "LKWEEKS should be in PERSON_COLUMNS"
+        assert (
+            '"WKSUNEM"' not in content
+        ), "WKSUNEM should not be in PERSON_COLUMNS (Census uses LKWEEKS)"
+
+    def test_cps_uses_lkweeks(self):
+        """Test that cps.py uses LKWEEKS, not WKSUNEM."""
+        cps_path = Path(__file__).parent.parent / (
+            "policyengine_us_data/datasets/cps/cps.py"
+        )
+        content = cps_path.read_text()
+
+        # Check for correct variable reference
+        assert "LKWEEKS" in content, "cps.py should reference LKWEEKS"
+        assert "WKSUNEM" not in content, "cps.py should not reference WKSUNEM"
+
+    def test_weeks_unemployed_value_range(self):
+        """Test that weeks_unemployed values are in valid range (0-52)."""
+        # LKWEEKS values: 0 = not unemployed, 1-52 = weeks, -1 = NIU
+        # After processing, should be 0-52 (NIU mapped to 0)
+
+        raw_values = np.array([-1, 0, 1, 26, 52, -1])
+        processed = np.where(raw_values == -1, 0, raw_values)
+
+        assert processed.min() >= 0, "Minimum should be >= 0"
+        assert processed.max() <= 52, "Maximum should be <= 52"
+        assert processed[0] == 0, "NIU (-1) should map to 0"
+        assert processed[1] == 0, "Not unemployed (0) should stay 0"
+        assert processed[3] == 26, "26 weeks should stay 26"
+
+    def test_puf_weeks_imputation_constraints(self):
+        """Test the weeks imputation constraints for PUF copy."""
+        # The QRF-based imputation should respect these constraints:
+        # 1. weeks should be in [0, 52]
+        # 2. weeks should be 0 when UC is 0
+
+        # Test constraint enforcement
+        raw_imputed = np.array([-5, 0, 25, 60, 100])
+        uc_values = np.array([100, 0, 5000, 10000, 0])
+
+        # Apply constraints like the function does
+        constrained = np.clip(raw_imputed, 0, 52)
+        constrained = np.where(uc_values > 0, constrained, 0)
+
+        assert constrained.min() >= 0, "Should be non-negative"
+        assert constrained.max() <= 52, "Should be capped at 52 weeks"
+        assert constrained[1] == 0, "No UC should mean 0 weeks"
+        assert constrained[4] == 0, "No UC should mean 0 weeks"
+        assert constrained[2] == 25, "Valid weeks with UC should be preserved"
+
+    def test_extended_cps_handles_weeks_unemployed(self):
+        """Test that extended_cps.py has special handling for weeks_unemployed."""
+        ecps_path = Path(__file__).parent.parent / (
+            "policyengine_us_data/datasets/cps/extended_cps.py"
+        )
+        content = ecps_path.read_text()
+
+        # Check for weeks_unemployed handling
+        assert (
+            "weeks_unemployed" in content
+        ), "extended_cps.py should handle weeks_unemployed"
+        assert (
+            "impute_weeks_unemployed_for_puf" in content
+        ), "Should have imputation function for PUF weeks"