Consumers wagered 133.3% more than in October last year, with the monthly amount beating the previous record of $408.3m set in September this year by 20.4%.
Players spent $483.3m betting online during the month, in addition to $8.1m at retail sites.
Football remained by far the most popular sports to wager on among bettors, with $171.2m bet in October. Basketball drew $63.3m in bets and college football $52.0m, while parlay betting amounted to $89.7m.