OBJECTIVES: To systematically review the measures of adherence to oral therapies employed in Brazilian observational studies. METHODS: Observational studies that evaluated adherence to oral therapies among Brazilian patients of any disease or condition were identified by searching Medline and LILACS, without time limits, using a combination of controlled vocabulary and text words for ‘adherence’. To be included studies had to fully report methods to assess adherece to oral drugs and be conducted with Brazilian patients. Studies examing only persistence measures or using lost to follow-up as a proxy to adherence were not deemed eligible. Articles were independently reviewed by two researchers to identify relevant studies and abstract methodological data. RESULTS: Of the 472 records identified, 61 full-text articles were included in the final version of this review. The most frequent therapeutic areas were Infectious Diseases (37.7%), Cardiology (24.6%), and Endocrinology (8.2%) – HIV/AIDS represented 36.1% of all studies, while High Blood Pressure contributed with 13.1% of the included papers. Sixteen studies adopted more than one adherence measures (81 differente evaluations in 61 studies). The most frequently used adherence measures were: self-reported (n=30, 37.0%), the Morisky test (n=19, 23.5%), and pharmacy records (n=7, 8.6%). Different versions of the Morisky test were identified (modified, 4-item, and 8-item). Other validated adherence questionnaires identified within the studies (with more than one occurence) were: MAT (n=3) and MedTake (n=2). Pill counting, medical chart review, and serum drug determination were used in 4 studies each. None study used electronic monitoring of adherence. CONCLUSIONS: Data from the available Brazilian studies indicate a variety of methods adopted by local researchers for measuring adherence to treatment. Indirect measures are more common, particularly those based on patients’ or caregivers’ perception of adherence behaviors. Most studies enrolled HIV/AIDS or hypertension patients. Other chronic conditions with long term continuous oral therapies were underrepresented.