Full text article. Also available at https://doi.org/10.1186/s12913-017-2809-8Global policy reports, national frameworks, and programmatic tools and guidance emphasize the integration of family planning and HIV testing and counseling services to ensure universal access to reproductive health care and HIV prevention. However, the status of integration between these two services in Tanzanian health facilities is unclear. This study examined determinants of facility readiness for integration of family planning with HIV testing and counseling services in Tanzania. Data from the 2014–2015 Tanzania Service Provision Assessment Survey were analyzed. Facilities were considered ready for integration of family planning with HIV testing and counseling services if they scored ≥ 50% on both family planning and HIV testing and counseling service readiness indices as identified by the World Health Organization. All analyses were adjusted for clustering effects, and estimates were weighted to correct for non-responses and disproportionate sampling. Descriptive, bivariate, and multivariate logistic regression analyses were performed. A total of 1188 health facilities were included in the study. Of all of the health facilities, 915 (77%) reported offering both family planning and HIV testing and counseling services, while only 536 (45%) were considered ready to integrate these two services. Significant determinants of facility readiness for integrating these two services were being government owned [AOR = 3.2; 95%CI, 1.9–5.6], having routine management meetings [AOR = 1.9; 95%CI, 1.1–3.3], availability of guidelines [AOR = 3.8; 95%CI, 2.4–5.8], in-service training of staff [AOR = 2.6; 95%CI, 1.3–5.2], and availability of laboratories for HIV testing [AOR = 17.1; 95%CI, 8.2–35.6]. The proportion of facility readiness for the integration of family planning with HIV testing and counseling in Tanzania is unsatisfactory. The Ministry of Health should distribute and ensure constant availability of guidelines, availability of rapid diagnostic tests for HIV testing, and the provision of refresher training to health providers, as these were among the determinants of facility readiness.