Today’s organizations are operating in a very dynamic and highly competitive environment. To remain relevant in the market, they have to be able to respond quickly to ever changing customer demands. Reward management is one of the ways used by organizations for attracting and retaining suitable employees as well as facilitating them to improve their performance. KPLC is an organization that offers essential energy services that support other sectors of the economy. The management has established rewards in their organization in pursuit of increasing employee performance so as to ensure prompt and quality service. However, the extent to which the rewards adopted at KPLC have influenced employee performance is not established. This study therefore aimed at determining the effect of reward on employee performance at KPLC. Specifically the study sought to determine the effect of cash bonus on employee performance. The research adopted correlation research design. 68 management employees responded. Data was collected using questionnaires. Descriptive statistics (frequency tables, percentages) were used to present data. Inferential statistics (chi-square) was used to analyze the relationship between cash bonuses and employee performance. Data was analyzed with the help of the Statistical Package for Social Sciences (SPSS) computer programme. The findings of the study showed that cash bonus have no effect on employee performance (p=0.8). This is because those who received cash bonuses and those who did not all agree that the cash bonus affects their performance the same. The organization should focus on changing the intrinsic nature and content of jobs. This will increase employee motivation as employees will get more autonomy more challenging job assignments and responsibilities. Further research can be done to find out impact of other rewards on performance e.g. owning equity. Research can also be done to identify other factors which may affect performance. Such findings can enhance management of performance.