Objective: The present study revealed mentoring relationship at work and association of mentor support with mentee job satisfaction and mental health. Methods: A web-based survey was administered to 2,028 managers and staff within large corporations; 1,283 responses (63.9％) were obtained, and 1,178 responses with full data were analyzed. Multiple regression analyses assessed the association between the amount of mentor support and mentee job satisfaction and mental health. Results: Male and female mentees receive support from multiple mentors within and outside of their organization. Male mentees receiving high career, psychosocial, and role-modeling support from mentors within the same organization showed greater job satisfaction and better mental health than non-mentees. Female mentees receiving low career support, as well as high/low psychological and role-modeling support from mentors within the same organization showed greater job satisfaction than non-mentees; however, no significant differences emerged regarding mental health for female mentees. Conclusions: Results revealed that mentors within the same organization are particularly important for maintaining and improving job satisfaction among male and female mentees as well as mental health for male mentees. However, some gender differences did emerge suggesting nuances regarding mentor support outcomes for men and women.