Sexual reproductive structure of Phytophthora capsici in vitro was round shape with thick wall and $24.4;{mu}m$ of diameter ranging $20-32.5;{mu}m$. Oogonium was $26.7;{mu}m$ $(21-37.5;{mu}m$) and $6.5-{ imes}5.4m$ $(6-8{ imes}5-6{mu}m)$ for antheridium as doughnut shaped. Since mycelial contact of the paired cultures initiated right after inoculation, mycelial expansion phase was followed. Oospore morphogensis could be divided into the four phases for reproducing adult oospores. The optimum temperature for oospore reproduction was $20-24^{circ}C$, whereas a retard trend for oospore formation was at the temperature above $25^{circ}C$. Korean squash agar medium showed a higher oospore formation than the existing V-8 agar medium. Red pepper fruit agar medium was next. No oospore was reproduced on the red pepper leaf medium. Diurnal light with $1800{pm}300$ and $800{pm}300$ Lux showed rather retardation for oospore formation than dark conditions.