The purpose of this study is to evaluate the impact of New Public Management (NPM) on Staffs Organizational Trust. Considering the extensive evolution in public administration field based on New Public Management Approach, and due to the lack of researches investigating the influence of NPM on Organizational Trust, in this research, we’ve tried to fill that gap. In this study, the Statistical population was 280 Municipality of Rasht staffs, of which; 165 people were selected by using the Cochran’s formula and the staffs were chosen by Simple Random Sampling method. For data analyzing, linear regressions coefficient and analysis of variance (ANOVA) were used. The results show that implementing the New Public Management principals in public sector (with coefficient 0.833), effects the Organizational Trust. It is also concluded from the results of Sub-hypothesis, that downsizing and privatization have not any meaningful relation with organizational Trust, but de bureaucratization, decentralization and managerialism, have a positive effect on Organizational Trust.