Person-perceived social participation is an important aspect to measure in rehabilitation in neuromuscular disorders. The objective was to document the test-retest and inter-rater reliability of the Assessment of Life Habits (LIFE-H), in a sample of individuals with myotonic dystrophy (DM1). Twenty-eight participants with myotonic dystrophy aged between 29 and 75 years (mean: 52.7) were recruited. The LIFE-H questionnaire was administered at three different occasions. The LIFE-H demonstrates high test-retest and inter-rater reliability (ICCs: 0.80-0.92) for the total score and subscores (daily activities and social roles). Moderate to high test-retest reliability (ICCs: 0.76-0.92) was found for most categories (8/10) of the LIFE-H. Similar results were obtained for inter-rater reliability (ICCs: 0.68-0.93). Moderate to high agreement using the Bland and Altman method was obtained for most categories. The LIFE-H, a measure of person-perceived social participation, demonstrates adequate test-retest and inter-rater reliability for clinical and research purposes in myotonic dystrophy.