AIM: This study aimed to measure the feasibility and acceptability of a theory-driven hybrid online-offline mentorship program and determine its impact on transition of newly graduated nurses. BACKGROUND: Excessive transition shock for newly graduated nurses can harm their well-being and increase nursing mistakes and patient issues. Therefore, helping newly graduated nurses in transitioning is crucial. DESIGN: A parallel 2-arm randomized controlled trial design was used. METHOD: The study randomly assigned 90 newly graduated nurses to receive either mentorship intervention or usual training. Two of them lost at the first follow-up and their data were not included in the outcome analysis. Outcomes included transition shock, job satisfaction and intent to stay. Generalized Linear Mixed Model was conducted to compare outcomes at baseline to follow-up. Semi-interviews with mentees and mentors were conducted for the qualitative part. Thematic analysis was used to code the qualitative responses. This report adheres to the CONSORT. RESULTS: At 6 months post-intervention, participants in the intervention group showed significant mitigation of rising levels of transition shock (Coef.=-0.223, p <
0.002) compared with the control group. Moreover, participants showed significant mitigation of declining of job satisfaction (Coef.=0.075, p <
0.05) and intent to stay (Coef.=0.435, p <
0.01). Qualitative findings showed participants' positive experience with the program. CONCLUSION: The study showed that the intervention not only effectively mitigated the transition shock for newly graduated nurses but also slowed the decline in job satisfaction and intent to stay, offering valuable insights for future nursing research, education and management.