The prevalence of attention deficit/hyperactivity disorder (ADHD) is rising in Thai children. The possible causes of this developmental disorder include environmental and genetic risk factors. Organophosphate (OP) and pyrethroid (PYR) are insecticides popularly used in agricultural areas. The epidemiological evidence on their potential neurobehavioral effects in children is lacking. This study aimed to clarify the relationship of levels of OP and PYR exposure and ADHD behaviors compared between children living in rice farming area and children living in aquacultural farming area. The cross-sectional study was done in 3 sessions: pilot, high (wet season) and low (dry season) pesticide use periods. Participants (N=53) aged between 6-8 years old were recruited. The first morning void of urine samples and blood cholinesterase were collected. Participants assessed the continuous performance test (CPT) form the Behavioral Assessment and Research System (BARS) and their parents completed the Conners ADHD questionnaires. Although the concentrations of urinary OP metabolites in participants living in rice area were significantly higher than participants living in aquacultural areas (Mann-Whiney U test, p