In this project, we have performed a comparative analysis of the proteomes of the mycelium and cysts of P. capsici. The identified proteins were functionally classified, which provides the basis for future research on these developmental stages of P. capsici and closely related species. Many of the proteins enriched in either the mycelium or cysts were found to contribute specific functions in these two life stages. Proteins enriched in mycelium were essentially associated with vegetative growth, whereas those enriched in cysts were primarily related to development-specific processes associated with the initiation of infection. The data provide a better understanding of the metabolic pathways underlying the mycelial and cyst developmental stages of P. capsici and point to potential targets of anti-oomycete compounds at each of these stages.