BACKGROUND/OBJECTIVES: We aimed to quantify the association of sarcopenia with length of hospital stay (LOS) and to identify factors associated with sarcopenia among hospitalized patients. SUBJECTS/METHODS: A total of 655 patients composed the study sample. A longitudinal study was conducted in a University Hospital. Sarcopenia was defined, according to European Consensus criteria, as low muscle mass (bioelectrical impedance analysis) and low muscle function (handgrip strength). Logistic regression, Kaplan-Meier and Cox adjusted proportional hazards methods were used. LOS was determined from the date of hospital admission and discharge home (event of interest). RESULTS: Participants were aged 18 to 90 years (24.3% sarcopenic). Factors associated with sarcopenia were male gender, age >= 65 years, moderate or severe dependence, undernutrition and being admitted to a medical ward. Sarcopenic patients presented a lower probability of being discharged home (hazard ratio (HR), 95% confidence interval (CI) = 0.71, 0.58-0.86). However, after stratifying for age groups, this effect was visible only in patients aged <65 years (HR, 95% CI = 0.66, 0.51-0.86). Moreover, sarcopenic overweight or obese patients presented a higher probability of being discharged home (HR, 95% CI = 0.78, 0.61-0.99) than nonoverweight sarcopenic patients (HR, 95% CI = 0.63, 0.48-0.83). CONCLUSIONS: Being male, age >= 65 years, presenting dependence, being undernourished and admitted to a medical ward were factors associated with sarcopenia among hospitalized adult patients. Sarcopenia is independently associated with longer LOS, although this association is stronger for patients aged <65 years. Moreover, sarcopenic overweight was associated with a higher probability of discharge home than nonoverweight sarcopenia.