is an American nonprofit that does research and advocacy for myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), Long COVID, and other post-infectious diseases.

Their stated mission is to assist research into ways to diagnose, treat, or cure these conditions.

They also advocate for increased awareness, public funding of research, and access to medical care for patients.

was founded in 1987[1][2] as the Chronic Fatigue Immune Dysfunction Syndrome (CFIDS) Association of America, and changed to its current name in the spring of 2014.

[6] They perform advocacy activities, such as contacting elected officials, and publishing materials for patients.