It happened on Jaye Street near the Tule River just after 6 pm.
Officers found the 25-year-old victim suffering from multiple stab wounds.
The victim was taken to Kaweah Health Medical Center in Visalia, but their condition has not been released.
Investigators are working to determine what led up the stabbing. Anyone with information is asked to call the Porterville Police Department at 559-782-7400.