The purpose of the present study was to empirically explore whether postal distance education programs have positive impact on job performance. To do this, this study reviewed the related literature based upon the system theory consisting of input-process-output. In particular, this study tried to identify the effectiveness of postal distance education on job performance, after controlling for input components such as the self-esteem, the learning readiness, and the support of organization. The questionnaire was distributed to 5,360 randomly selected employees who have at least one time taken any postal distance education programs in the past 12 months. As a result, there were 405 usable questionnaires, yielding a response rate of 7.56%. During the field test, reliability and face validity were established. Through the factor analysis, construct validity was established as well. To address the research purpose, descriptive statistics, correlation analyses, and hierarchical regression analysis were used. Finally, after controlling for input components, 9% of variance of job performance was statistically explained by the process variables of postal distance education. The adequacy of learning content, the adequacy of evaluation, operators\' facilitation of learning, and the convenience & usefulness of LMS were identified as meaningful variables. In particular, operators\' facilitation of learning was the most important in terms of explaining the variance of job performance. As a result, postal distance education programs can be a main actor on the stage of HRD. Based upon the findings, some implications were discussed.