Gas chromatography analysis for organochlorine insecticides was performed in 195 blood samples from individuals belonging to 5 groups according to levels of exposure: a) control group with low exposure; b) city dwellers; c) workers in greenhouse floriculture; d) workers doing spraying for malaria control; e) workers mixing insecticides. All the samples had DDT which was expressed as total DDT (DDT + DDE). For the five groups these values were (mean and Range in ppb): a) 18 (3-69); b) 13.6 (3-69); C) 18(3-28); d) 26 (5-57); e) 35 (6-91). Lindane was found in 6% a, 10%b, 14% e. Dieldrin in 8% a, 10%b, 10% e, 16% d and 94%-(mean 8.5 ppb) e. Heptachloride epoxide 5%e, 8% d and 35% e. The reported measurements are representative and the level of contamination can be considered equal to or lower than that reported in otrher countries.