Aims: The aim of this study was to investigate the prevalence of astrovirus infections and associated risks factors. Methods: A prospective study was undertaken from May 2009 to March 2010, covering the rainy and dry seasons, at the Saint Camille Medical Center in Ouagadougou, Burkina Faso. A total of 213 non hospitalized children less than 5 years of age with diarrhea were enrolled and examined for astrovirus, others enteropathogens, and clinico-epidemiological aspects. Results: Astroviruses prevalence among the enrolled children was 14.6%. Astrovirus infections were common during the cold dry season from December to February (38.7%), during the rainy season from June to September (54.8%), also during dry season in March (3.2%) and May (3.2%). Children younger than 11 months of age were most affected by astroviruses (16%). Moderate and severe malnutrition influenced more severe symptoms of astrovirus related diarrheas. Conclusion: The present study shows that astroviruses have an important role in pediatric viral-associated diarrhea in Burkina Faso. Diarrhea is more severe in malnourished children.