Mouse Parvovirus (MPV) is one of the most prevalent infectious agents in modern laboratory mouse colonies. Unlike other infectious agents, modern-day implementation of barrier facilities, quarantine procedures, and routine colony monitoring have not eliminated the presence of this virus in all research mouse colonies. MPV infection results in sub-clinical signs and no gross pathology. However, MPV infection has an appreciable immunomodulatory effects both in-vitro and in-vivo. The mechanisms responsible for these effects are poorly defined. The results of a small preliminary study are presented. These showed that MPV might have the potential to significantly alter pregnancy rates and cytokine profiles of infected mice. Control mice had a pregnancy rate of 57% (4/7) and MPV infected mice had a pregnancy rate of 10% (1/10). Additionally, cytokine expression profiles appeared to be influenced by MPV infection. This small study is the first known report of MPV infection resulting in alterations of reproduction and cytokine profiles in mice.