Aspiration pneumonia is believed to be an uncommon complication of amyotrophic lateral sclerosis (ALS). However, the incidence of aspiration pneumonia and its contribution to morbidity and mortality are unknown in ALS. All cases of ALS from Olmsted County, Minnesota from 1990 to 2005 were reviewed. Baseline demographics were noted for all cases. Dates of diagnosis, PEG tube placement, death and survival status were also noted. All cases of aspiration pneumonia were identified. Forty cases of ALS were identified over the 15-year period. The incidence rate was 1.7 cases per 100,000 person years. There was an overall mean survival of 26 months from diagnosis. Aspiration pneumonia occurred in five (13%) cases. There was a mean survival of two months following aspiration pneumonia. The strongest risk factor for aspiration pneumonia was nursing home residence with a relative risk of 7.1 (p = 0.02) We conclude that the incidence rates and demographics of our ALS population have remained stable over time. Aspiration pneumonia occurs in a minority but is associated with a high mortality. ALS subjects residing in nursing homes are at the greatest risk.