Three of the methods most often used for the clean-up and fractionation of organochlorine pesticides in lipid residue analysis by gas chromatography with electron-capture detection were compared. The overall recoveries of twenty pesticides from spiked samples were higher than 88%, the relative standard deviation being in the range 3-11% (n = 6) at the 36-80 ppb (10(9) level. The three methods were compared by analysis of variance, with no differences in precision at the 0.05 significance level. Differences in recoveries appeared in only two instances. None of the three methods seems to be significantly better than the others for the determination of the pesticides studied.