Managing factors that affect the inventory management practices increase its performance and boost the achievements of the organizational goal. The main objective of the study is to identify factory affecting the effectiveness of inventory management practices in the Werabe agricultural research center of Central Ethiopia. To achieve this, both descriptive and explanatory research designs were employed, utilizing qualitative and quantitative methods. The study used census-sampling technique because Census is a process of collecting data by distributing questionnaire to all population in the study area. Data was collected through questionnaires and secondary sources and analyzed using both inferential and descriptive statistics with SPSS version 21. The results reveal that factors such as qualified staff, funding, documentation, and information technology significantly influence effectiveness of inventory management practices. Among the independent variables, qualified staff and information technology had a positive significant effect on effectiveness of inventory management practice while funding and documentation had a strong positive relationship with effectiveness of inventory management practices. Thus, the study recommended that the Werabe agriculture research center have to allocate sufficient budget for inventory management and the documentation system of the organization needs improvements of the manual documentation systems through by automating system, will increases effectiveness of inventory management system.