[eng] The aim of the study was to validate the Spanish version of the Nursing Self-Concept Instrument (NSCI) for nursing students, while also describing its relations with clinical practice and professional quality of life (PQL). A cross-sectional survey was conducted. Analyses included the study of item-objective congruence, descriptive statistics, competitive confirmatory factor analyses, reliability estimates, and a structural model. Criterion-related validity evidence was studied by hypothesizing, estimating, and testing a mediation model. Item-objective congruence values indicated adequate content validity. Regarding dimensions, the lowest mean was found for leadership, whereas the highest was for care. The two tested models showed adequate fit. Reliability was adequate. The mediation model in which clinical experience explained the levels of nursing self-concept and PQL showed excellent overall fit. Dimensions of nursing self-concept and PQL showed adequate factor loadings. Results showed a statistically significant relation between clinical practice, nursing self-concept, and PQL. The NSCI for nursing students has adequate psychometric properties. A positive impact on PQL and the relationship between appropriate experiences and higher levels of nursing self-concept has been demonstrated.