Rotavirus is the main cause of severe, dehydrating diarrhoea in infants and young children. In industrialized countries, pediatric rotavirus gastroenteritis (PRGE) is responsible for high morbidity, particularly among children under 3 years of age attending day care centers (DCCs). The objectives of this study were to estimate the incidence, management and cost of PRGE in DCCs. We also described the nature of group A rotavirus genotypes. This study also compared the performance of different diagnostic techniques. The study was conducted from November 2004 to May 2005. Children aged less than 36 months, attending a participating DCC at least 4 times a week were included in the study. For any episode of acute gastroenteritis (AGE), defined as the occurrence of 3 or more watery or looser than normal stools and/or forceful vomiting within a 24 h period, a fecal specimen was tested by Elisa test IDEIA Rotavirus (Dako) and the immunochromatographic test VIKIA Rota-Adeno (BioMérieux). Sequencing by RT-PCR was performed to identify the rotavirus genotype. Among the 41 DCCs contacted, 18 (43.9%) agreed to participate. Out of 966 children, 547 attended a participating DCC at least 4 times a week and met the inclusion criteria. A total of 302 were included in the study. The clinical diagnosis of AGE was confirmed and validated, by the Elisa test, in 63 fecal specimens, of which 29 (46%) were positive for rotavirus antigen, with a predominance of P[8]G9 (86%). Our results showed good sensitivity and specificity for the VIKIA and Elisa methods when compared to RT-PCR. Among the PRGE cases, 36% were male and the median age was 12.2 months. The first rotavirus case was observed in December 2004 with a peak in January 2005. The incidence of PRGE cases was 2.2 [1.4-3.0] per 100 child-months in children aged less than 36 months of age, increasing to 3.4 per 100 child-months among children aged less than 24 months. Vomiting (P<0.0005) and behavior modification (P<0.001) were significantly more frequent for PRGE cases. A total of 85.7% PRGE cases sought medical attention. In 58.3% of these cases, at least one parent had to miss work for a mean duration of 2.1 days. The total cost of rotavirus cases seeking medical attention (with or without prescribed medication, days off work for parents or additional diaper consumption) was estimated at 275.54 euros/case. The PRGE incidence rate is similar to that estimated in European studies conducted in DDC. These findings confirm that rotavirus transmission occurs not only in DCCs but within the family. This is the first study to give an estimate of the incidence and the cost of rotavirus infection in DCCs in France.