This study explains how organizational citizenship behavior (OCB) is an important concept in organizational behavior. According to this study, organizational justice perception ( distributive and procedural justice) is a predictor of OCB at the workplace. Based on theory, distributive and procedural justice are strong predictors of OCB. This research was executed in small business companies where 34 subject who consisted of full time employees were gathered. The results supported all hypotheses which mean that distributive and procedural justice has strong predictive capacity to employees' OCB at the workplace.