Hospitalization is associated with nutritional deficiencies, hypokinesia, and pronounced inflammatory response. These factors can exacerbate muscle mass loss, increase the hospital stays, and morbimortality. In this scenario, muscle anabolism through nutritional stimuli and muscle contraction emerges as potential therapeutic strategies. Aim: To investigate the effect of protein supplementation combined with neuromuscular electrostimulation on muscle mass and functionality in hospitalized elderly. This is a double-blind, randomized clinical trial. Inclusion criteria were elderly individuals (≥65 years old) of both sexes, admitted in the last 12 hours and capable of oral feeding. Exclusion criteria were cancer in the past 5 years, musculoskeletal or neurological diseases, and dietary restrictions. The patients were divided into two groups: intervention (INT) and standard of care (STD). The INT group received 60g of whey protein daily, divided into two doses, and neuromuscular electrostimulation sessions for the lower limb. The STD group received an isocaloric blend with carbohydrates and sessions that mimicked the electrostimulation. The cross-sectional area of the lateral vastus muscle was examined (CSAVL, using ultrasound scan), and functionality (Short Physical Performance Battery-SPPB) were evaluated upon admission and discharge from hospital. Breakfast, lunch, and dinner intake were quantified daily. The relative difference was calculated, and the groups were compared using the Student t-test. The significance level was set at P ≤ 0.05, and a P < 0.1 was considered a trend towards statistical significance. Fifteen patients were recruited (INT: n=8, STD: n=7). The INT group presented higher absolute (84 vs. 41g/day, P<0,01) and relative (1.3 vs. 0,6g/kg/day, P<0,01) protein uptake compared to STD. Calories, carbohydrates, and fat uptake were similar between groups (P>0,05). Relative difference analysis revealed a trend towards a smaller reduction of CSAVL after hospitalization in INT group, compared to STD group (-7% vs. -15%, P=0,07). The INT group demonstrated a trend towards better performance (reduced time) of gait speed test compared with STD group (-12% vs. 9%, P=0,07). No significant difference was observed in the sit-to-stand test (INT: -2% vs. STD: 6%, P=0,72) and total score of SPPB (INT: 10% vs. STD: 5%, P=0,48). Hospitalization time was similar between groups (INT: 11 vs. STD: 10, P=0,68). The preliminary results suggest that protein supplementation plus neuromuscular electrostimulation may reduce muscle impairment in hospitalized elderly individuals. However, due to the limited sample size, it is necessary to interpret these results with caution.