Background and aim: Physical mobility is often described as a basic prerequisite for independence, self-determination, and social participation. Older people, particularly those in long-term care facilities, are more often affected by the loss of their mobility. However, the prevalence of the mobility disabilities of nursing home residents and their association with demographic and care-specific/medical factors have so far been studied less. This prevalence study should investigate a possible association of mobility disability with age, BMI, multimorbidity, fall risk, and social participation. Methods: The prevalence study covered the data of residents in 30 German residential care facilities (RCFs). Trained staff nurses used a standardised instrument to collect data about the age, obesity, medical diagnoses, the fall risk, the level of mobility disability, and the need for supporting the social participation of the residents. Results: The representative sample included 2,066 nursing home residents, of whom 81.5% required support in their mobility. The level of a mobility disability or the need for a support in matters of mobility by others was not associated either with age, with the BMI, or with the fall risk of the participants. The groups with higher mobility disability included the more multimorbid participants with more difficult medical diagnoses, and these had a higher need for support in their social participation. Conclusions: It may be that professional care must reflect the premature link between older and obese patients with mobility disability. In addition to nursing diagnoses, medical diagnoses should necessarily be integrated into the nursing assessment. The association between the level of mobility disability and the fall risk, which is often mentioned in the literature, should be critically reflected. Nursing home residents should be informed that there is a possible association between their mobility disability and their social participation.