Objectives: The study aimed to assess the degree of adherence to immunosuppressive medications and to identify the factors related to adherence in kidney transplant patients. Methods: A prospective, descriptive study was performed in a nephrology outpatient clinic between November 2017 and February 2018. All kidneytransplant patients had a face-to-face interview with a clinical pharmacist. The data on patients’ demographics and blood drug concentrations were recorded and the Immunosuppressive Therapy Adherence Scale was administered at the clinic. The factors that may affect medication adherence were evaluated among the groups of adherent and non-adherent patients. Results: The study included 100 kidney transplant patients. With regard to immunosuppressive medication, 67, 26, and 7 patients were using tacrolimus, cyclosporine, and everolimus, respectively. Only 32 patients had an Immunosuppressive Therapy Adherence Scale score of 12 (known as adherent). Blood drug concentrations of tacrolimus were found to be sig nificantly different between adherent and non-adherent patient groups (P = 0.005). Except with body mass index (P = .019) and post-transplantation period (P = .041) no statistical association was found between the rest of the factors and adher ence. The most common problem with drug usage was inappropriate time of drug administration (64.0%). Conclusion: A significant proportion (68%) of kidney transplant patients were non-adherent to immunosuppressive medi cation. Adherence to immunosuppressive medication can be influenced by patient-related factors such as body mass index and post-transplantation time. Therefore, healthcare professionals should be aware of the level of a patient’s adherence and factors affecting patient adherence level. A clinical pharmacist may play a critical role in identifying a patient’s level of adherence to maintain effective therapy.