New research shows more than 1.6 million adults place bets on sporting events.
According to the Philip Lee Sport Report published by Amarach, 60% of gamblers go in store to place a bet. However, people aged between 25-to-34 years are more likely to place a bet online.
The report examines public attitudes and habits in relation to sport and fitness. It also shows that people spend €2.4bn on sport and exercise-related activities in Ireland each year.
The Irish public spends nearly €450m on sports clothing, footwear and equipment and €255m on sports club membership annually.
Philip Lee said the research showed sport plays a key role in Irish society.
"This sends a clear message that sport is big business," he said. "Reports also show that €1 spent on sport can deliver benefits of €5 in terms of better health and reduced crime."