Background: Organizational justice has recently been introduced as a new concept as psychosocial determinants of employee health, and an increase in precarious employment is a challenging issue in occupational health. However, no study investigated the association of organizational justice with mental health among employees while taking into account employment contract. Purpose: The purpose of the present study was to investigate the prospective association of organizational justice (procedural justice and interactional justice) with psychological distress by employment contract among Japanese employees. Methods: A total of 373 males and 644 females from five branches of a manufacturing company in Japan were surveyed. At baseline (August 2009), self-administered questionnaires, including the Organizational Justice Questionnaire (OJQ), the K6 scale (psychological distress scale), the Eysenck Personality Questionnaire-Revised (EPQ-R), and other covariates, were used. After one-year follow-up (August 2010), the K6 scale was used again to assess psychological distress. Multiple logistic regression analyses were conducted by sex and employment contract. Results: After adjusting for demographic characteristics, psychological distress, and neuroticism at baseline, low procedural justice was significantly associated with a higher risk of psychological distress at follow-up among non-permanent female employees, while no significant association of procedural justice or interactional justice with psychological distress at follow-up was observed among permanent male or female employees. The results of non-permanent male employees could not be calculated because of small sample size. Conclusions: Low procedural justice may be an important predictor of psychological distress among non-permanent female employees. © 2012 International Society of Behavioral Medicine.