International researchers have urged greater use of simple neurobehavioral batteries in developing country settings where higher levels of exposure and a variety of cultural and demographic factors may both occur. We conducted a cross-sectional survey of 144 farm members and 72 age and education frequency-matched controls from rural Ecuador, using an amplified Neurobehavioral Core Test Battery. Farm members ranged from those with only indirect pesticide contact to applicators regularly applying organophosphate and carbamate insecticides by backpack sprayer. The distributors of scores showed those with less than 4 years of formal education and at the extremes of age (< 16 or > 65 years old) contributed sufficiently to nonnormality that they had to be excluded from subsequent analyses (resultant n = 170). After adjustment for age and education, language-based IQ test scores and farm membership were the most consistent determinants of neurobehavioral outcomes. Visual-spatial tasks were the most sensitive to the effects of farm membership. Gender (women better than men), alcohol problems, and solvent use were also important for some neurobehavioral tests.