A precise and sensitive high performance liquid chromatographic (HPLC) method is proposed for determining aflatoxins in cottonseed products in 1.0—1.5 hr. After aqueous acetone extraction, lead acetate treatment, and partition of aflatoxins into methylene chloride, sample extracts are purified on a small silica gel column requiring only 125 ml solvent/sample. Aflatoxins B1 and B2 in the purified extract are resolved on a micro particulate (10 μm) silica gel column in ca 8 min, using a water-saturated chloroform - cyclohexane - acetonitrile solvent, with detection by ultraviolet absorbance at 365 nm. The resolution was highly reproducible, giving coefficients of variation of 0.2—1.0% for retention and 1.0—2.3% for quantitation. Recovery of added aflatoxins B1 and B2 was 90— 95% at levels of 5—100 μg/kg. The within-laboratory coefficients of variation of the entire method, based on repetitive assays of a cottonseed meal (34 μg B1/kg, 6 μg B2/kg), were 7.3% (B1) and 7.4% (B3). A high degree of correlation was obtained for HPLC estimation by 2 different commercial columns; for quantitation by peak height vs. electronic integration; and for quantitation by HPLC or thin layer chromatography.