Porcine cytomegalovirus (PCMV) is an ubiquitous infectious agent in swine population throughout the world. Field and some experimental observations have suggested that PCMV plays an important role in causing or enhancing respiratory and/or reproductive disease of swine. However, no actual measure of this has been documented. As the first step in assessing the economic significance of PCMV infection for swine herds in the United States, a field-based case-control study was conducted to evaluate the potential role of the virus in respiratory disease of young swine. The data in this study, thus far, suggest that there may be an association between PCMV infection and increased risk of respiratory disease development in nursery pig populations and that, as was expected, PCMV infection is a common finding among nursery pigs. In an era in which multifactorial respiratory disease and associated decrease in production efficiency is such a large concern, it may be prudent to consider PCMV when developing and implementing strategies for production management and pig flow