Rotaviruses are the leading cause of community-acquired and nosocomial gastroenterocolitis in children. There is little data concerning the epidemiology of nosocomial rotavirus gastroenterocolitis (NRVG) in Central European countries. The aim of our study was to analyze the epidemiology of NRVG in a pediatric hospital in Warsaw, Poland, where the majority of children was admitted due to respiratory tract infections. Retrospective chart analysis of 49,697 patients aged 0-18 hospitalized during 2006-2009 was performed. NRVG was defined as acute gastroeneterocolitis (>3 loose stools in 24 h or vomiting), confirmed with A rapid immunochromatographic test, if symptoms developed >48 h after admission. In total, 469 cases of NRVG were diagnosed. The cumulative attack rate of NRVG for the hospital was calculated as 0.97% (CI 0.86-1.02), the cumulative incidence density was 2.07/1000 bed-days (CI 2.01-2.13). The majority of NRVG were diagnosed at the General Pediatrics Ward (206 cases, 44%) and Allergology and Pulmonology Ward (122 cases, 26%), where the mean duration of hospital stay was longer than 5 days (9.9 ± 1.0 and 6.1 ± 0.8 days, respectively). Primary causes of hospitalization of the children with nosocomial rotavirus gastroenterocolitis were respiratory tract infections (including pneumonia, bronchitis, and otitis media) present in 287 cases (61.2%). The nosocomial rotavirus infection was mostly diagnosed among patients aged 6 months - 2 years (201 cases, 42.8%), less common were infections among infants younger than 6 months (133 cases, 28.3%) and children aged 2-6 (115 cases, 24.5%). The mean age of a child with NRVG was 16.2 ± 10.2. In conclusion, rotavirus gastroenteritis is the most important nosocomial infection in children hospitalized due to respiratory tract infections and can prolong their hospital stay.