The verdict was reached in San Diego Superior Court, where the 35-year-old former NFL player was also found guilty of indecent exposure and lewd conduct but not guilty of one count of a lewd act.
Prosecutors used DNA evidence and pointed to GPS locations that placed Winslow where the women said the assaults happened to make their case while the defense argued inconsistencies in the accuser's stories and that the sex was consensual.
The jury is still deliberating on two more counts of rape, which involve a 54-year-old hitchhiker and an unconscious teenage girl, the latter of which allegedly occurred in 2003 when Winslow was 19.
All five women testified while Winslow did not take the stand during the nine-day trial.
If Winslow is found guilty of all counts, he could face up to life in prison. If not, he could serve as few as eight years.
Winslow, son of Hall of Famer Kellen Winslow Sr., played nine seasons in the NFL, which included stints with the Browns, Buccaneers and Patriots before finishing his career with the Jets in 2013.