Iodine is an essential mineral. This mineral is indispensable as thyroid forming substance, which is produced by the thyroid gland. The performance of the thyroid gland could be disrupted by the pesticide, when used excessively. Disorders occur in the process of thyroid hormone synthesis, which is on the receptor TSH (Thyroid Stimulating Hormone) in the thyroid gland. Thyroid hormone synthesis become inhibited because TSH can not enter the thyroid gland. It also inhibits the work of enzymes that act as catalyst for changes in T4 and T3 (active forms of hormones in the body). The presence of pesticides in the body is indicated by levels of cholinesterase in the blood. This study was conducted to know the profile of farmers exposed to pesticides, measure levels of cholinestrase (CHE), TSH levels in the blood of farmers, and analyze the relationship of pesticide residues (blood cholinestrase levels) to thyroid function (TSH level). Subject of research (N) was 109 farmers. Characteristic data were obtained by interview using structured instruments. Levels of TSH and T4 were analyzed by ELISA method. Cholinesterase was measured by spectrophotometry. Test kit was used to test the quality of salt. The results of this study showed 7.3% of farmers have cholinesterase levels below normal limits; 4.6% of farmers have high levels of TSH; and 6.4% of farmers have T4 levels below normal values. It is concluded that farmers with subclinical hypothyroidism and low-levels of poisoning are still found. However, there is no relationship between pesticide residues and thyroid function in farmers.