Rotavirus vaccines were introduced in Belgium in 2006 and recommended in the universal schedule in January 2007. We measured the impact of rotavirus vaccination through an active laboratory-based surveillance system. In 2008, the number of laboratory confirmed rotavirus cases declined by 61.4% (95% CI 60.2-62.6%) compared to the 2005-2006 pre-vaccination period, with the highest decline in children<1 year (80.1%; 95% CI 78.7-81.4%). The rotavirus season was delayed compared to pre-vaccination seasons. Laboratory data provide a crude estimation of vaccination impact, but analysis of in-patient data will be needed to assess the impact on severe disease.