Developmental prosopagnosia (DP) is a neurodevelopmental condition characterized by face recognition problems. Psychometrically sound self-report measures of face recognition problems are important tools in classification of DP. A widely used measure of such problems is the 20-item prosopagnosia index (PI20). Here, we present a Danish translation of the PI20 (PI20DK). We administered the PI20DK alongside three objective measures of face and object processing performance to 119 participants to validate the PI20DK. Further, we assess the underlying factor structure of the PI20DK. Finally, as the first study in the field, we investigate the association between self-reported face recognition ability and face perception performance. The project was preregistered prior to data collection. The results suggest excellent convergent validity, discriminant validity and internal consistency for the PI20DK. A confirmatory factor analysis, however, indicates a suboptimal fit of the PI20DK to a one factor solution. An investigation of the association between the PI20DK and face perception suggests that the poor fit may reflect that the PI20DK measures problems with face recognition in general and not specifically face memory problems.