Due to development of Information and Communication Technology (ICT), microfinance industry in Tanzania has experienced rapid growth over the years in an attempt to meet the large demand of clients lacking access to financial services. Despite of the challenges, there has been a tremendous growth of ICT utilization in MFIs, different applications and technologies have been adopted by some MFIs to enhances business processes, control costs, create efficiency and effectiveness in their operations, improve productivity, and increase outreach to the poor. The specific focus of this study was on assessing the ICT utilization on microfinance institutions performance in Tanzania. With the specific objectives of examining the performance of current ICTs usage level on Microfinance institutions, Determining the ICT contributions to microfinance institution performance, Examine the challenges facing ICT on microfinance institution performance. The study was conducted at Opportunity Microfinance Tanzania Limited in Mbagala, Chanika, Manzese and Kiluvya wards in Dar Es Salaam City-Tanzania. The population of 73 respondents which included IT officers, Operations Managers, Head of Department, Sales Officers, Clients and Tellers were selected from four branches of Opportunity Microfinance Tanzania Ltd and 73 questionnaires distributed and thus were collected respectively, purposive sampling was used and the data collected was analyzed using SPSS and chi-square test. The finding indicates and established that ICT utilization has direct relationship with microfinance institution performance in Tanzania. ICT help microfinance to improve the efficiency and effectiveness of services offered to customers, enhances business processes, improve managerial decision making, better online and offline support of customers and strengthens particular microfinance competitive positions in the market. There are however, many microfinance institutions in Tanzania where ICTs have not fully adopted and utilized to all functional areas. Therefore, this study recommended that MFIs should get specialized, independent consultant, this is due to the fact that sometimes MFIs choose technologies that may not be right for the MFI at a given time, also MFIs might fail to choose systems that will support business over long time. Due to that specialized, independent consultants can bring an objective perspective and help MFIs set strategic priorities, assess technology requirements, and manage technology vendors. Choosing a proper MIS does not mean just looking at the IT system but it means looking at the organisation as a whole and identifying the strengths and weaknesses of the structure. The study also recommends that internal ICTs challenge to be resolved through proper training, i.e. the provision of ICT related training to employees with respect to the strategic and operational management of the microfinance and also recruit external specialized consultants.