The purpose of this study is to evaluate the association between pesticides and neurological symptoms among a population exposed to organophosphate chemicals as a result of agricultural use. Chronic sequelae of acute pesticide poisoning from organophosphate compounds include a variety of neurological symptoms including restlessness, irritability, and trouble sleeping. Individuals who have had an acute pesticide poisoning have been reported to suffer a wide range of neurological symptoms that occur from weeks to months after the initial episode. Data for this study came from a cross-sectional survey of farmers and their spouses conducted in an eight-county area in north-eastern Colorado. Neurological characteristics were assessed to determine their relationship with previously reported pesticide-related illnesses. Symptoms that were significantly associated with a previous poisoning were difficulty concentrating [OR 2.07, 95% confidence interval (CI) 1.22, 3.50]; relatives noticing person had trouble remembering things (OR 2.54, 95% CI 1.47, 4.39); making notes to remember things (OR 2.18, 95% CI 1.20, 3.97); finding it hard to understand the meaning of newspapers, magazines, and books (OR 1.90, 95% CI 1.01, 3.60); felt irritable (OR 1.84, 95% CI 1.08, 3.12); felt depressed (OR 2.82, 95% CI 1.65, 4.81); had heart palpitations without exertion (OR 2.83, 95% CI 1.22, 6.54); sleeping more than usual (OR 3.58, 95% CI 1.95, 6.58); difficulty moving fingers or grasping things (OR 2.08, 95% CI 1.06, 3.24); and headaches at least once a week (OR 1.85, 95% CI 1.06, 3.24). Stepwise regression was used to identify the best explanatory model of pesticide-related illness. Variables that were associated with increased odds of illness were being male, being depressed, sleeping too much, and using crop organophosphates.