The current study was an attempt to investigate the impact of a comprehensive Performance Management System on Organizational Performance, while analyzing the mediating effect of employee performance and moderation of organizational justice in five Cellular Phone Companies (CPC) of Pakistan. The study was based on the gaps found in previous literature which emphasized on analyzing the effectiveness of performance management system in terms of its employee and organizational outcomes. Survey techniquewas employed for which a questionnaire comprised of multiple borrowed scales was used, which was revalidated in Pakistani context. Data were collected from 271 managers of Cellular Phone Companies of Pakistan. The study involved moderation, mediation and moderated-mediation analyses, for which Preacher and Hayes’ PROCESS MACRO (Model 1, 4 and 8) was used. The results of the study reflected significant moderation of organizational justice, partial mediationof employee performance and significant moderated-mediation effects of both on relationship between performance management system and organizational performance. It was established that comprehensive performance management system, duly supported by perception of organizational justice within the organization, leads to enhanced employee and organizational performance. The researcher also conducted multivariate analysis of variance (MANOVA) and Post Hoc analysis to analyze the differences of performance management system and organizational justice practices among the five cellular phone companies of Pakistan. From theoretical perspective, thecomprehensive performance management system framework comprised of seven dimensions, was usedfor the first time especially in the Pakistani context. Moreover, the moderating effect of organizational justice on performance management system was also researcher’s contribution. The study has also revalidated goal setting, expectancy and equity theory in Pakistani context. Results of the study suggested the cellular phone companies to focus on comprehensive performance management system incorporating goal setting, communication, establishing & monitoring performance expectations, coaching, feedback, performance appraisal and performance consequences along with positive perception of organizational justice in Pakistani context to achieve the objectives of enhanced employee and organizational performance. The study has also provided implications for future research in the area.