Sarcopenia is a syndrome characterised by a progressive and generalised loss of skeletal muscle mass and strength with a risk of adverse outcomes such as physical disability, poor quality of life and death. The main aim of the present study was to establish the prevalence of sarcopenia using EWGSOP-defined criteria in institutionalised older adult patients in long-term care institutions. Asecondary purpose was to identify the risk factors that develop Sarcopenia in this population. A Multicentre cross-sectional study was conducted in 334 institutionalised older adult patients, where the prevalence of sarcopenia and its relation with certain risk factors were measured. Physical performance was measured by gait speed, muscle strength measured by a handheld dynamometer and skeletal muscle mass measured using bioimpedance analysis. Different variables were collected: body mass index (BMI), diseases documented in the clinical record, the numbers of falls, the level of activity and functional ability. Two hundred eighty five individuals were included. According the EWGSOP algorithm and the cut-off points proposed by Masanes etal. for the Spanish population, 118 (41.4%) participants presented sarcopenia, of which 32 patients (27%) suffered from moderate sarcopenia, 78 patients (66%) were identified as severe sarcopenia patients and only 8 (7%) were classified as sarcopenic obesity. More female residents (96 females (81.4%) vs. 22 males (18.6%), p<0.0001) tended to be sarcopenic. Patients diagnosed with sarcopenia tended to be more functionally impaired and had a more unfavourable BMI than those who were not sarcopenic (Barthel score 40.93 vs, 49.22, p=0.0034 and BMI 23.57 vs, 27.61, p<0.0001). Results from regression analysis indicated that those older than 85 years old (OR 2.495, 95% CI 1.401-4.441), the female gender, (OR 3.215, 95%CI 1.635-6.324) and whose BMI was lower than 22 (OR 5.973, 95% CI 2.932-12.165) appeared to be associated with sarcopenia, whereas the Barthel Index and other factors were not. The present study suggests that sarcopenia is highly prevalent in patients living in long-term care institutions, especially in female patients. Our findings support that the muscle mass was negatively associated with poor nutritional status and poor capacity to develop basic activities of daily living that indicates high dependency of these patients and high necessity of care.