We performed a study on mortality from motor neuron disease in the province of Bologna, Italy, during the years 1986 through 1988. The study was based on death certificates from the Cancer Registry of the Province of Bologna. We verified death certificates for both false-positive and false-negative cases. The crude mortality rate was 1.93/100,000 population per year. The age and sex mortality rate, standardized on the Italian population, was 1.40/100,000 (95% confidence interval, 1.05 to 1.83). Our figures are higher than those previously reported both as the incidence and as mortality in Italy, but these data are similar to values that have been found in northern Europe and in North America.