Present study examines the relationship between perceived organizational support (POS) and organizational commitment and the mediating role of organization based self-esteem between these variables. 148 white collared employees participated to the study. Results indicated a significant relationship between POS and affective commitment and normative commitment, but a negative relationship between POS and continuance commitment. Results reveal that organization based self-esteem (OBSE) has a partial mediating role between perceived organizational support and affective commitment and full mediating role between perceived organizational support and continuance commitment. Findings also indicate that OBSE has no mediating role between perceived organizational support and normative commitment.