The purpose of this study was to determine the effect of work discipline, work motivation, work environment, and communication on the performance of PT KAI Daop 5 Purwokerto employees. This research is a quantitative study using a questionnaire of 135 respondents to employees of PT KAI Daop 5 Purwokerto. The sampling technique used is saturated sample technique. The data analysis techniques used in this study were descriptive statistical analysis, instrument testing, classical assumption testing, data analysis testing, model fit testing, and hypothesis testing. The results of the study show that work discipline, work motivation, work environment, and communication simultaneously have a significant effect on employee performance. (a) Work discipline partially has a positive and not significant effect on employee performance, (b) work motivation partially has a positive effect and significant effect on employee performance, (c) the work environment partially has a negative and insignificant effect on employee performance, (d) communication has a positive and significant effect on employee performance.