Introduction: quality is an integral part in EPI. Being pastoralist life style, poor infrastructure was considered the main reasons behind low coverage in this region. Therefore, the main aim of this study was to assess the quality of EPI service delivery in primary health care institutions of jigjiga zone Somali of region. Method: institution based cross-sectional study was carried out to assess the status of EPI service in PHCU of Jijiga zone, Somali region, from December 2011 to March 2012. Institutions were selected based on simple random sampling technique using mixed approaches. Results: This study has described the characteristics of quality of EPI service input, service process and service outcome main finding disclosed by this study, showed that almost the service is accessible to the care takers, most of the institution visited have adequate logistics and supplies and the service providers claiming, more than half of the mothers were satisfied with EPI services. The overall satisfaction in this study was 53.3%. Out of 422 study participants, 405 (96%) of the mothers/care takers were satisfied with the reception of the health workers. Conclusion: the study showed that half of the mothers yet not satisfied with the quality of the services. Therefore, to improve client satisfaction, waiting time should be kept as short as possible, in-service training/communication skill, outreach allowance should be considered for the service providers should be concerned woreda health offices, and further study in the area has to be made to dig out more factors affecting the service utilization of EPI.