To test for associations between occupation and median nerve dysfunction, measures of median motor and median and ulnar sensory amplitude and distal latency were compared among three populations: control subjects without occupational exposure to highly forceful or repetitive hand exertions (N = 105), industrial workers with hand/wrist symptoms (N = 103), and asymptomatic industrial workers (N = 137). Mean sensory amplitudes were significantly smaller (p < 0.05) and motor and sensory distal latencies were significantly longer (p < 0.001) in the industrial "asymptomatic hand" population compared to the control population. Prolongation of median relative to ulnar latency was significantly longer in the asymptomatic industrial population (p < 0.05). Results were most plausibly explained by differences in checklist identified ergonomic stressors. Median sensory amplitudes were significantly smaller (p < 0.01) and latencies longer (p < 0.05) for industrial workers with exposure to high grip forces compared to those without. Exposure misclassification may have reduced power to detect statistically significant differences between exposed and nonexposed population groups.