This study aimed to examine the factors associated with intentions to leave among newly graduated nurses (NGNs), using a longitudinal design. We distributed self-administered questionnaires (to be returned anonymously) to all the NGNs (n=567) in nine advanced treatment hospitals in Japan on two separate occasions (Time 1 and Time 2, which were approximately 6 months apart). The questionnaire items addressed individual attributes, employment and organizational characteristics, and subjective health, and also included the 22-item Job Content Questionnaire, a scale of intentions to leave, and a novel 21-item job readiness scale. The data from 301 NGNs who had participated in both questionnaire instances was used, and a hierarchical multiple regression analysis was conducted to investigate the factors associated with intentions to leave. The results showed that while psychological distress was a more important predictor of intentions to leave than was cumulative fatigue at Time 1, cumulative fatigue was a more important predictor at Time 2. Among the job stressors, a lack of coworker support consistently led to increased intentions to leave, while a lack of supervisor support had a greater impact on intentions to leave at Time 1. “Being personally suited for nursing work”, which was one of the job-readiness subscales, was found to independently and consistently influence intentions to leave. Our study findings revealed the predictors of intentions to leave among NGNs early in their careers in Japan.