In the county of Orebro, Sweden, 32 individuals with myotonic disorders and 25 with other types of muscular dystrophy were examined. Disability was assessed with functional tests and standardized observations of muscle function (mainly based on those proposed by Dr. Brooke), a new self-administered questionnaire regarding the Activities of Daily Living (ADL) and the ADL staircase (based on Katz ADL index). The results of the different tests of disability were highly correlated. The Sickness Impact Profile and the Kaasa test were used for assessing the quality of life, and no significant differences were found between the groups of muscular dystrophy. In an explanatory factor analysis three main factors of disability were found. The factors "walk and move" and "finger function" were fair to good associated with the quality of life. This study offers an approach for research on the consequences of muscular dystrophy using established as well as new methods.