Chlorpyrifos (a pesticide containing phosphorous and chlorine) from oil matrix was determined using gas chromatography (GC) with a flame photometric (FPD) and electron capture (ECD) detectors. In the first experiment, the detector (FPD) used gave recoveries (from palm olein samples spiked with chlorpyrifos at levels of 0.04-0.10 μg ml^-1) ranging from 89% to 100% with coefficients of variation from 2.9% to 10.8%. In the second experiment, ECD showed recoveries (from palm olein spiked with chlorpyrifos at levels 0.02-0.10  μg ml^-1) of greater than 97% with coefficients of variations ranging from 0.5% to 2%. The results showed that using GC, the ECD and FPD are suitable detectors for quantification of chlorpyrifos in oil matrix.