One of the most important tools for improving the relative efficiencies of any organization is to establish suggestion system. Having a reliable system, which could reflect all employees' comments and concerns, helps managers take necessary actions to remove any possible obstacle in the system. In this paper, we measure efficiency and effectiveness of suggestion system in the National Iranian Oil Products Distribution. We also provide practical suggestions for improvement and necessary actions required to review the system. The proposed study of this paper uses a sample of 297 people from 1294 employees who work in different position for some of the regional offices of this firm in north part of Iran. The study has used two separate questionnaires, where the first one consists of 40 questions in Likert scale trying to measure the efficiency and effectiveness of the suggestion system. In addition, we use another questionnaire to rank important factors detected in the first stage. The results of questionnaires have been analyzed using different statistical tests.