Over 10% of acute rotavirus gastroenteritis (ARGE) requires hospitalization because of complications. The aggravating factors have been widely analysed, but in an isolated way. We aimed to explore the interrelationship between the clinical and epidemiological factors that characterize rotavirus hospitalizations in Spain using information from the Minimum Basic Data Set (MBDS). Using ICD-9-CM codes, we classified acute gastroenteritis (AGE) cases by principal diagnosis fields and then categorized their comorbidities, complications, and epidemiological features by secondary fields. A multivariable, logistic, step-wise regression model was then constructed. We identified 1657 ARGE cases from 17 415 cases of AGE. Rotavirus hospitalizations were associated with place of residence, age, and season (P < 0·0001), as well as with dehydration [odds ratio (OR) 12·44, 95% confidence interval (CI) 1·52-40·38], intravenous rehydration (OR 1·74, 95% CI 1·29-2·35), metabolic acidosis (OR 1·51, 95% CI 1·24-1·83), respiratory tract infections (RTIs) (OR 1·60, 95% CI 1·09-1·98), and concomitant AGE (OR 1·52, 95% CI 1·03-2·25). Dehydration was four times more likely in patients aged <5 years (OR 4·36, 95% CI 1·20-12·96) and was associated with acidosis when ARGE and RTI were present simultaneously (P < 0·0001). Specific co-infecting viruses may play a role in acute respiratory symptoms and aggravation of gastrointestinal manifestations of rotaviruses, thus leading to complications requiring hospitalization.