This research to explore the influence of motivation and organizational culture on employee performance at PT Pos Indonesia Kebonrojo Surabaya through organizational commitment. In this case, motivation and organizational culture are considered important in creating good performance in a company. This research uses a quantitative method using a questionnaire which is used to collect data and the population in this research is 250 with a sample of 71 respondents obtained using the Slovin formula. Data analysis uses the Partial Least Square (PLS) method. The research results show that motivation has a positive and significant influence on employee performance, as well as on organizational culture. Apart from that, motivation positively and significantly influences employee performance through organizational commitment and organizational culture also positively and significantly influences employee performance through organizational commitment. These findings show that there is a mutually influencing relationship between motivation, organizational culture, organizational commitment and employee performance at PT Pos Indonesia Kebonrojo Surabaya.