The aim of the study was to investigate factors related to the use of restraints and to explore whether the rate of nurses was an influencing factor regarding the use of restraints in German nursing homes and hospitals. Restraints are frequently used measures in hospitals and nursing homes. Risks for falls and small nurse workforces are discussed in relation to the use of restraints. A secondary analysis of a cross-sectional study was carried out. Methods. Data were collected by trained nurses using standardised questionnaires in 76 nursing homes (n = 5521) and 15 hospitals (n = 2827). For data analysis, a 3-level random intercept logistic model was used. The prevalence of restraints (bed rails and/or belts) was 9·3% for hospital patients and 26·3% for nursing home residents. Amongst hospital patients, restraint use was more prevalent in women, older patients, patients with a high care dependency, patients who fell during the last two weeks, patients with a perceived risk of falls, polypharmacy, urinary incontinence, disorientation and confinement to bed. In the nursing homes, the restrained residents were significantly younger, more care dependent, had less falls and were more often urinary incontinent, disoriented and bedfast. The rate of nurses was not significantly related to the use of restraints in hospitals, and nursing homes according to the three-level random intercept model. Hospital patients with previous falls were more often restrained, but in the nursing homes, the restrained residents experienced less falls. The number of qualified nursing staff had no significant influence on the use of physical restraints. Lower nurse staffing ratios were not related to higher frequencies of restraint use in this study.