Running back LaMichael James, guard Joe Looney, linebacker Darius Fleming, safety Trenton Robinson, offensive lineman Jason Slowey and linebacker Cameron Johnson all signed four-year deals with the 49ers.
James was a second-round pick who rushed for 5,082 yards at Oregon. He led the nation with 150.4 rushing yards per game last season.
Looney was a fourth-round pick out of Wake Forest, while Fleming was a fifth-round selection out of Notre Dame.
The other three were late-round picks: Robinson was selected in the sixth round out of Michigan State, while Slowey (Western Oregon) and Johnson (Virginia) were seventh-round picks.