A Dissertation Submitted in Partial Fulfillment of the Requirements for the Award of Master of Science in Accounting and Finance (Msc. A&F ) of Mzumbe UniversityThis study of Assessment of use of Accounting Information System in decision making for the public sector is conducted in Agricultural Research Institute UYOLE (ARI-UYOLE) in Mbeya region. The main objective was to examine the effectiveness of the use of Accounting Information System in decision making for ARI-UYOLE as a case study. The research methodologies employed included interviews by the use of unstructured questions, which directed mainly to staff of ARI-UYOLE. The second method involved structured questions in a written form (questionnaires) to capture the required data. Thirdly, observation method was applied and in this case the researcher physically visited ARI-UYOLE and at projects sites of the respondents and this took three consecutively, months to accomplish the task. Lastly documental source were used to obtain mostly the secondary data. The findings from the study revealed that the staff skills lack necessary knowledge for producing qualitative information which leads the interpretation of financial information for decision making to be difficult to some users. Also the technology used to process the information is outdated and it takes too long to receive relevant information and wanted the researcher to find the alternative ways to shorten the situation. So the study proposed the following recommendations to ARI-UYOLE:-Most of staffs are to be retained for proper effectiveness of Accounting Information System so as to produce the qualitative information. Also the technology used should be relevant to enable the users to reduce the cycle time of Accounting Information System process so as to assist the decision making in ARI-UYOLE.