How many hours can an ovum survive in a fallopian tube?

Upon ovulation, the ovum goes into the Fallopian tube, where it can survive for approximately 12 to 24 hours. As this is a critical period of time for the ovum, it is necessary for a sperm to readily available for fertilization. The sperm can be already present from previous intercourse, or upon having had sex and the male ejaculates, the sperm travels through the uterus and up the Fallopian tube to meet the egg.