The patient-reported outcome measurement information system (PROMIS^®) initiative has developed and evaluated a set of publicly available, efficient, and flexible measures of patient-reported outcomes in different health domains, including mental health. The objective of this study was to translate the PROMIS Depression item bank into German and evaluate the psychometric properties of the translated items. Items were translated using forward and backward translation and cognitive interviews. Distribution characteristics, unidimensionality, Rasch model fit, reliability, construct validity, and internal responsiveness were investigated in a sample of 234 patients in in-patient psychosomatic rehabilitation centers in Germany. The translated items showed good psychometric properties, the distribution characteristics were satisfactory, and the sufficient unidimensionality was obtained by fitting a bifactor model. The construct validity was demonstrated, and it was reliable and was shown to detect clinically significant changes. The translated items can be recommended for the assessment of depression. Future studies should examine the generalizability of the results.