They competed in the NSWRL's 1990 Winfield Cup premiership and again improved on their previous year, finishing the regular season in second position before going on to come within one match of the grand final, but losing to eventual premiers, the Canberra Raiders.
Broncos players Chris Johns and Kevin Walters were selected to make their international débuts for the Australia national rugby league team in 1990.
[1] In order to increase the Broncos' success in the Winfield Cup, Wayne Bennett controversially sacked Wally Lewis as club captain and gave the role to centre Gene Miles.
Miles had retired from representative football, and Bennett hoped he could remove the team's reliance on Lewis.
At the end of the season, Wally Lewis parted company with the Broncos, moving to the Gold Coast Seagulls.