An epidemiological investigation of 41 subjects with amyotrophic lateral sclerosis observed in the Province of Messina during 1976–1985 was performed. The incidence was 0.61/100,000 and the prevalence 2.48/100,000 inhabitants. The illness was found to be prevalent in males. The atrophic type occurred in 17 subjects, the bulbar type in 23 cases and the pseudo-polyneuritic form in only one patient. The mean age on the onset was 57.29 ± 10.55 years. The duration of the illness was significantly higher in patients with atrophic type (p < 0.01). No significant difference between occupation and development of the disease was found. Among all patients 12.19% presented evidence of trauma, but traumatic events were equally present in a control group.