Este artigo está licenciado sob forma de uma licença Creative Commons Atribuição 4.0 Internacional, que permite uso irrestrito, distribuição e reprodução em qualquer meio, desde que a publicação original seja corretamente citada. ABSTRACT AIMS: To assess the functionality of individuals of a same family who present Kennedy's disease, and to compare it with the results obtained after one year and a half to verify the evolution of the disease. METHODS: Case series, in which six individuals with Kennedy's disease were evaluated in two moments separated by one year and a half. The instrument used was the Core Set for International Classification of Functioning, Disability and Health for neuromuscular diseases. This structured questionnaire seeks information on health domains, functional situations and their restrictions. The data were analyzed in SPSS version 20.0, with descriptive analysis. RESULTS: After one year and a half the body function components worsened, with consequent decline in function, demonstrated in the activity and participation component. Only one domain of the body function component had improvement in the second evaluation. During the evaluation period, several facilitating environmental factors (bars or stair rails, internal bars in residences, ramps, health plan, gaiters, automobile, telephone and electronic gate) remained. However, the magnitude of the deficiency of some products and supporting technologies (stairs and bathroom without bars) increased, which may have impaired the functionality of these individuals. CONCLUSIONS: Functionality was altered in individuals with Kennedy's disease, and the disease progression has accentuated the deficiency in the components of the International Classification of Functionality after one year and a half. There was a lack of some supporting products and technologies to personal use in daily life.