This study aims to explore the relationship between earning management and investment decision of the firms. Secondly, to also check the impact of such investment decision and earning management on performance of firms. For this purpose data of 164 listed manufacturing companies has been used over the period of eleven year from 2006 to 2016. Special items variable has been used as proxy for earning management. Performance of firms has been measured through accounting based indicators including ROA, ROE, ROCE, EPS, and GP. Results of this study shows that firms engaged in earning management through special items manipulation also over invest in the same period. Consequently, such excessive investment and manipulation through special items negatively impact the performance of firms. Supervisor:- Dr. Ahsan ul Haq Satti