This proposed study will provide additional sites for the CDC/ATSDR’s Amyotrophic Lateral Sclerosis and Other Motor Neuron (ALS/MND) National Disease Registry Study and is being submitted to the Centers for Disease Control and Prevention Agency for Toxic Substances and Disease Registry (CDC/ATSDR) by members of the HMO Research Network (HMORN). The United States Congress, through proposed Senate Bill 1351 (109th Congress), has shown a strong interest in establishing a national ALS registry. This interest stems from uncertainty about the incidence, prevalence, and about the total economic burden of ALS. The estimates of the annual incidence rate range from 0.2 cases per 100,000 population to 2.4 cases per 100,000 population. The estimates of ALS prevalence range from of 0.8 cases per 100,000 population to 7.3 cases per 100,000 population. Ten-fold variation in estimates of incidence and prevalence rates is unacceptable for providing accurate estimates of the disease’s economic burden and for determining whether these patients have access to high-quality health care. An ALS registry would also provide valuable infrastructure for identifying incident and prevalent cases of ALS for research. The CDC/ATSDR has initiated a series of coordinated research and demonstration projects to test alternative methods for tracking ALS incidence and prevalence.