Introduction: Hospital malnutrition is a prevalent problem that cause higher morbidity and mortality, poorer response to treatment and higher hospital stay and cost. Objectives: To determine the prevalence and factors associated with hospital malnutrition in a peruvian General Hospital. Methods: Cross-sectional study including 211 hospitalized patients in Medicine and Surgery wards. Demographic, clinical and anthropometrical indicators' data was collected. Multivariate analysis was binary logistic regression. All tests had a significance level of 5% (p < 0.05). Results: Prevalence of hospital malnutrition was 46.9%. Prevalences of caloric and protein malnutrition were 21.3% and 37.5%, respectively. Bivariate analysis found that hospitalization in Surgery wards was associated with a major risk of caloric (OR = 4.41, IC 95% [1.65-11.78]) and protein malnutrition (OR = 2.52, IC 95% [1.297-4.89]). During the analysis of quantitative variables, significant associations between number of comorbidities and caloric malnutrition (p = 0.031) was found, and also between the beginning of food intake changes and the presence of protein malnutrition (p = 0.031). Multivariate analysis showed significant association between diagnosis of neoplasm and presence of caloric malnutrition (OR = 5.22, IC [1.43-19.13]). Conclusions: Prevalence of hospital malnutrition was near 50%, as in similar studies. Protein-caloric malnutrition prevalences obtained, differ from the ones in a previous study in this hospital, which is explained by the different diagnostic criteria and particular characteristics of groups of patients, such as procedence ward and comorbidities. An association between protein-caloric and hospitalization in a Surgery ward was found; the reasons should be investigated in further studies.