Aims: Chronic Chagas disease (ChD) has high morbimortality and loss in quality of life due to heart failure (HF). Pharmaceutical care (PC) optimizes clinical treatment and can improve quality of life in HF. We evaluated if PC improves quality of life of patients with ChD and HF. Methods: Single-blinded, randomized, controlled trial that assigned adult patients with ChD and HF (81 patients; 61±11 years; 48% male) to PC (n=40) or standard care (n=41). Quality of life according to SF-36 and Minnesota Living with HF (MLHFQ) questionnaires, incidence of drug-related problems (DRPs), and adherence to medical treatment were determined at baseline and at every 3 months for one year. Intention-to-treat analyses were performed by mixed linear model to verify the treatment effect on the changes of these variables throughout the intervention period. Results: Relative changes from baseline to one year of follow-up of the domains physical functioning (+16.6 vs. -8.5;p<0.001), role-physical (+34.0 vs. +5.2;p=0.01), general health (+19.4 vs. -6.1;p<0.001), vitality (+11.5 vs. -5.8;p=0.003), social functioning (+7.5 vs. - 13.3;p=0.002), and mental health (+9.0 vs. -3.7;p=0.006) of the SF-36 questionnaire and the MLHFQ score (-12.7 vs +4.8;p<0.001) were superior in the PC group than in the standard care group. Adherence to medical treatment increased as early as after 3 months of follow-up and DRPs incidence decreased after 6 months of follow-up only in the PC group. Conclusions: Patients with ChD and HF who received PC presented improved quality of life, decrease in DRPs frequency, and increase in medication adherence.