Objective. To assess nurses’ knowledge, attitudes and practices (KAP) towards spontaneous adverse drug reactions (ADRs) reporting. Methods. The mixed-method study was conducted following a quanti-qualitative sequential approach: a survey (using a KAP questionnaire) followed by a focus group was performed. ,Results. In the quantitative findings, responders (570 hospital nurses) declared that they were unaware of the pharmacovigilance system (58.1%, n = 331); where to find the reporting form (63.5%, n = 362); how fill it in (71.6%, n = 408); to whom and how to send it (65.8%, n = 375). Only 11.1% (n = 63) reported ADRs. The qualitative phase supported the quantitative findings and provided new information about other factors that condition ADR reporting: misinterpretation of the meaning of “reporting”, unawareness of nurses’ autonomy in ADR reporting and fear of consequences after ADR reporting. Conclusion. Nurses are not fully aware of their role in ADR reporting. We recommend educational interventions and management changes.