A crossover 8-wk study was conducted to compare the effects on plasma lipoproteins and endogenous sex hormones of lean white fish (LWF) and of beef, pork, egg, and milk (BPEM) within a prudent diet in postmenopausal women. Diets provided 8050 kJ as 19% proteins, 52% carbohydrates, 29% lipids (P/M/S (proportion of polyunsaturated, monounsaturated, and saturated fatty acids, 1.1:1:1) and approximately 210 mg cholesterol/d. The LWF diet compared with the BPEM diet significantly induced higher concentrations of plasma cholesterol, LDL-apo B, HDL-C, and HDL3-C, indicating that incorporation of LWF as a substitute for BPEM in a low-fat, high-P:S diet offers little benefit with regard to plasma cholesterol and LDL-apoB in postmenopausal women. Moreover, the LWF diet significantly increased plasma SHBG, suggesting that the divergent effects of substituting LWF for other animal-protein sources on plasma cholesterol and lipoproteins may be partly mediated by variations in plasma sex-hormone status.