The study was conducted in order to investigate adherence in patients with Rheumatoid arthritis (RA), correlating it with other variables such as affect and self-esteem. Seventy-eight patients with RA between 20 and 81 years of age were evaluated. Patients were assessed for Medical Outcomes Study (MOS) Measures of Patient Adherence, Rosenberg self-esteem scale and Short Portuguese version of the Positive and Negative Affect Schedule (PANAS). Pearson's correlation coefficient was used to assess the correlation between the therapeutic compliance and age, disease activity, disability, GPA, self-esteem, affect and inflammatory parameters. An independent T-test was used to evaluate differences in adherence within gender. The one-way analysis of variance (ANOVA) was used to determine associations between adherence and marital status, education level and employment status. A linear regression model was adjusted with stepwise data entry to determine predictors of therapeutic compliance. Patients had a mean age of 57 years and disease duration of 12.8 years. We observed higher levels of adherence in patients with higher self-esteem (r= 0.343, p<0.05) and positive affect (r= 0.345, p<0.01). The adjusted linear regression model allowed the identification of positive affect as a RA patient's adherence predictor (R = 0.347, p<0.05). In our study, high levels of self-reported adherence in RA patients were found. Positive affect seems to be an important determinant of therapeutic adherence in RA patients. These results suggest a relevant role of psychosocial aspects in therapeutic compliance and outcome, which should alert physicians to the need of an holistic approach of the patient.