Improving nursing students' attitudes towards patient safety is a current and relevant topic. This study aims to evaluate the effectiveness of an educational intervention based on critical incident and root cause analysis (RCA) techniques regarding attitudes towards patient safety in nursing students. A quasi-experimental before and after study was developed between January 2018 and December 2019 in a sample of 100 nursing students at Universitat Jaume I (Spain). The intervention was developed in two phases. Phase I was at university, where students applied the RCA technique in a real case. Phase II took place during clinical practice. Students used critical incidents to identify a risk situation for the patients and applied RCA to detect its root causes. The measurement of attitudes was performed with the Attitudes to Patient Safety Questionnaire (APSQ-III). The global score of the questionnaire in the baseline measurement was 3.911 (±0.335), in the intermediate measurement it was 4.031 (±0.337) and in the final measurement it was 4.052 (±0.335), with significant differences (p = 0.03). However, intra-group differences were observed in the final measurement (p = 0.021). The teamwork dimension had the highest mean score on all three measures and the notification dimension had the lowest mean scores. An educational intervention combining critical incident and RCA techniques can improves nursing students' attitudes toward patient safety