The exposure assessment study was conducted in the southern Punjab, the cotton growing area of Pakistan among two female groups, one as cotton pickers (occupationally exposed) and the other group as non-pickers. The average blood cholinesterase activity before the spraying in non-pickers were found to be 5.32 ± 0.70 kU/L with the average activity of female cotton pickers 5.31 ± 1.12 kU/L. Whereas, due to environmental contamination the average activity of enzyme cholinesterase (ChE) was calculated to be 4.80 ± 1.08 kU/L in non picker's blood samples, collected after exposure to pesticides (post-season) as compared to 2.81 ± 1.32 kU/L in female cotton pickers. All these values were found be in the normal range. The mean values of ChE were found significantly different (1.95) among various groups when statistically analyzed by Z-test (α = 0.05). The effects of pesticides found equal in both groups of female were discussed in detail with common symptoms observed in majority of cotton pickers.