The Centers for Disease Control/Agency for Toxic Substances and Disease Registry (CDC/ATSDR) is seeking investigator-initiated research that will further the understanding of potential risk factors for Amyotrophic Lateral Sclerosis (ALS), while supporting the National ALS Registry's mission. The National ALS Registry's goals are to estimate the number of new ALS cases each year, estimate the number of people who have ALS at a specific point in time, better understand who gets ALS, and identify what contributing factors, including environmental, may affect ALS. CDC/ATSDR is seeking investigator-initiated research that will identify and evaluate risk factors contributing to ALS, with preferred focus in this Notice of Funding Opportunity on factors related to military service, contact sports, traumatic brain injury, neuroinflammation, environmental exposures, and infectious agents. Research proposals on preferred topics can be funded under one of two funding options, Funding Option A or Funding Option B.Funding Option A is intended to support ALS risk factor research investigations that have an existing, well substantiated evidence base and would benefit from strengthened rigorous evaluation. Funding Option B is intended to support novel ALS risk factor research investigations that may or may not have an existing evidence base foundation base, may be supported by limited and insufficient preliminary research, and are exploratory and developmental in nature.For Option A and B applicants may elect to use data from the National ALS Registry. Note, this is not compulsory and will not preclude the applicant from consideration.