OBJECTIVE: To describe changes of function in terms of sickness impact over 10 years in adult patients with different types of muscular dystrophy. DESIGN: Patients with muscular dystrophy answered the Sickness Impact Profile and Self-report ADL questionnaires in 1991 and 2001. SETTING: The study population was identified in a comprehensive prevalence study in the county of Orebro, Sweden. SUBJECTS: The study group comprised 44 people grouped according to whether they had myotonic dystrophy or muscular dystrophy with proximal or distal muscles affected. MAIN MEASURES: Comparison was made between assessments of sickness impact in terms of function at the two time points. RESULTS: Most obvious deterioration over time was in activities of daily living that require finger and arm strength. Ambulation was significantly decreased in myotonic dystrophy and proximal muscular dystrophy. Those walking without assistive devices decreased from 91% to 52%, and the number with a disability pension increased from 36 to 55%. There was a relatively small influence with regard to psychosocial dysfunction assessed by the Sickness Impact Profile. CONCLUSIONS: This longitudinal study shows the deteriorating functions reported by patients with muscular dystrophy. This knowledge could be used to formulate new interventions in order to offer appropriate support and treatment to this patient group.