Service quality is the key to loyalty members (consumers). To achieve a good quality of service, the Koperasi Baytul Ikhtiar Kota Bogor is required to provide excellent service to its members by taking into account the dimensions of the quality of services that include direct evidence, reliability, responsiveness, assurance, and empathy. Professionally managed institution will give priority to the quality of services because it will affect customer satisfaction (members) which would then affect the level of consumer loyalty (members).  The purpose of this study was to determine the effect of service quality on loyalty of cooperative members in the Koperasi Baytul Ikhtiar Kota Bogor, to determine whether the quality of services that include direct evidence (tangibles), reliability (reliability), responsiveness (responciveness), assurance (assurance), and empathy (empathy) berpenngaruh on member loyalty  The sample used a number of 50, the sampling technique with purposive sampling. This research is a field research with quantitative descriptive approach. The data used are primary data and secondary data. Primary data were obtained based on respondents' answers to a questionnaire distributed to the members of the Koperasi Baytul Ikhtiar Kota Bogor. Methods of data analysis using simple linear regression, descriptive variables ananlisis research and hypothesis testing (test t), and data processing using SPSS 20.0 for Windows.  From the results of the research data processing simple linear regression Y = 4.623 + 0,187X and the magnitude of the direct influence of service quality to loyalty members was 33.8%. Based on t test showed that the number sig. alpha of 0.000 below 5%, which means service quality significantly influence the loyalty of members of the Koperasi Baytul Ikhtiar Kota Bogor. Based on the coefficient of determination can be seen that the independent variables explain the dependent variable of 33.8%, while the remaining 66.2% is explained by other variables which in this case is not the subject of the study authors.