Este artigo está licenciado sob forma de uma licença Creative Commons Atribuição 4.0 Internacional, que permite uso irrestrito, distribuição e reprodução em qualquer meio, desde que a publicação original seja corretamente citada. ABSTRACT AIMS: To evaluate the characteristics and risk factors related to the adherence to immunosuppressive treatment of renal transplant patients using the self-report method by means of the Basel Assessment of Adherence Scale for Immunosuppressives (BAASIS). METHODS: A prospective cohort study with a quantitative approach was performed at the Nephrology and Transplantation Service of São Lucas Hospital of the Pontifical Catholic University of Rio Grande do Sul, with patients older than 18 years, transplanted from kidneys from deceased or living donors, with a minimum transplant time of three months and a maximum of 12 months. The BAASIS instrument was applied to evaluate adhesion. For statistical analysis, Fisher exact test (Monte Carlo simulation) was used to verify the association between the categorical variables, Student t test for independent sample means and Mann Whitney test in the variables without normality. A p<0.05 was adopted for the results to be considered significant. RESULTS: The sample consisted of 59 patients, 57.6% of whom were male, 79.7% were white, the mean age was 45.8 years, 57.6% had elementary school and 72.9% were catholic. Hemodialysis was the most used method, in 86.4% of patients before transplantation, and the mean time in the waiting list was 19.5 months. After transplantation, the mean time of hospitalization was 17.2 days. The assessment of adherence by BAASIS characterized 83% of patients as non-adherent. The main fact considered as non-adherence was to take the immunosuppressive drugs with more than two hours difference from the prescribed time, at least once a week, in the last four weeks. There was no significant difference when the statistical analysis was performed to compare the adhesion rate among the various categories of the demographic and clinical variables of the patients. CONCLUSIONS: A high rate of patients not adherent to the immunosuppressive treatment was identified, and the change in the schedule of immunosuppressants was the main fact that characterized this behavior. A shorter waiting time in the transplant queue was associated with non-adherence. The other variables, demographic and clinical, were not associated to the classification of adherent or non-adherent.