Aims and objectives: To develop a new scale for assessing the associative stigma of mental illness in nursing based on Peplau's model of psychodynamic nursing and to examine its psychometric properties. Background: The stigma of mental illness continues to cause problems today for patients, families and mental health professionals. For individuals with a mental disorder, stigma can result in restricted opportunities, social exclusion and the denial of rights. Associative stigma in mental health professionals is becoming a major problem and is related to increased depersonalisation, higher levels of emotional exhaustion and diminished job satisfaction among mental health professionals. Nursing may play a key role in reducing the stigma associated with mental illness, but there are no specific scales for the measurement of associative stigma in nursing. Design: Development of an instrument. A STROBE checklist was completed. Methods: This study involved two stages: (a) item generation and content validation; (b) examining the reliability and convergent/discriminant validity of the scale. A developmental and methodological design was used. Data were collected between November 2016-December 2017 from a sample of 737 nursing undergraduates. Results: The results indicated good internal consistency for the final 20-item scale for assessing the associative stigma of mental illness in nursing, which is considered in terms of three dimensions: Violence/Dangerousness, Disability, and Irresponsibility/ Lack of Competence. Exploratory and confirmatory factor analyses supported a three-factor structure consistent with the theoretical model. Conclusions: The 20-item EVEPEM (from its Spanish acronym) derived from Peplau's theory was shown to be a valid and reliable tool for assessing the stigma of mental illness in the nursing setting. Relevance to clinical practice: Reliable instruments are needed to measure the effectiveness of anti-stigma interventions for mental health professionals. The results indicate that the tool developed is a valid and reliable instrument for use in the nursing setting. K E Y W O R D S mental health, mental health nursing, nursing, nursing models, psychometrics | 4301 SASTRE-RUS ET Al.