Lipedema is a condition characterized by swelling and enlargement of the lower limbs due to abnormal deposition of subcutaneous fat. Lipedema is an under-recognized condition, often misdiagnosed as lymphedema or dismissed as simple obesity. We present a series of pedigrees and propose that lipedema is a genetic condition with either X-linked dominant inheritance or more likely, autosomal dominant inheritance with sex limitation. Lipedema appears to be a condition almost exclusively affecting females, presumably estrogen-requiring as it usually manifests at puberty. Lipedema is an entity distinct from obesity, but may be wrongly diagnosed as primary obesity, due to clinical overlap. The phenotype suggests a condition distinct from obesity and associated with pain, tenderness, and easy bruising in affected areas.