Objective The objective of this work was to compare two generic questionnaires assessing patients’ satisfaction with medication. In addition we tested whether satisfaction can predict adherence to medication regimens in patients with chronic diseases, and which dimensions of satisfaction are most involved. Methods This prospective, observational study was conducted over one year in a heterogeneous population of patients with various chronic diseases. Satisfaction with medication was assessed by using the TSQM？ vII and the SatMed-Q？ questionnaires, and adherence to treatment was assessed with the Morisky-Green questionnaire. Clinical pharmacists interviewed patients to collect clinical, demographic and therapeutic data. Results 190 patients were enrolled. Both questionnaires showed excellent reliability and correlation was high (R = 0.70; p<0.001). Adherence was correlated with satisfaction with medication whether assessed with the SatMed-Q？ (R = 0.23; p = 0.002) or the TSQM？ (R = 0.17; p = 0.02). Among different dimensions of satisfaction, convenience of use and side effects are prominent predictors of adherence. Conclusion Adherence is related to the patient’s satisfaction with medication whether assessed with the TSQM？ vII or the SatMed-Q？. Therefore, these simple questionnaires could be used as predictive tools to identify patients whos’ adherence needs to be improved.