Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder, characterized by progressive loss of motor neurons. However, ALS has been recognized to involve several non-motor systems, subclinically. Cardiac and sudomotor autonomic involvement in ALS has been described. Recently, delayed gastric emptying was reported. The aim of this study was to assess colonic transit time in patients with ALS. Therefore, measurement of total and segmental colonic transit times using radio-opaque markers was performed in 14 patients with ALS and 14 healthy age-matched volunteers. Multiple-ingestion, single-radiograph technique was used. Segmental and colonic transit times were calculated from the number of retained markers. Nine of 14 patients with ALS showed markedly delayed colonic transit times if compared to healthy controls. Colonic transit in ALS patients was significantly delayed in the right and left colon; the rectosigmoid transit did not show major delay. The colonic transit times did not correlate with bulbar involvement, Norris score, walking disability or duration of the disease. In summary, colonic dysfunction in ALS may be a result of inactivity or inadequate fiber intake. However, it also may represent a gastrointestinal autonomic involvement due to nerval degeneration. Considering ALS as a multisystem disorder including the autonomic nervous system may have implications for research into pathogenesis and therapy of neurodegenerative disease.