The authors observed a patient who worked in a farm and suffered an organophosphate intoxication (trichlorfon). The immediate effect was manifested by vomiting and abdominal cramps. Three months later he presented a distal symmetric sensorimotor (predominantly motor) neuropathy with distal muscle atrophy. Electromyography has revealed denervation changes in every muscle studied and the sensory and motor nerve conduction was slowed in arms and legs. The sural nerve biopsy specimen studied by light microscopy with semi-thin section and teased fiber preparation showed axonal degeneration. The ultrastructural studies of the axonal alterations consisted of degeneration of the neurofilaments and the neurotubules with granular appearance of the axoplasm.