Background and aims: Purchasing loot boxes in digital games is akin to gambling as it involves risking money for a chance-based reward of uncertain value. Research has linked buying loot boxes to problem gambling amongst adolescents, but has not examined co-occurring gambling participation. This study examined links between loot box purchasing and problem gambling amongst adolescents while controlling for monetary gambling participation. Methods: Two survey samples of Australians aged 12-17 years were recruited through advertisements (n 5 843) and online panels (n 5 826). They included n 5 421 and n 5 128 adolescents, respectively, who met criteria for problem gambling. Results: Past-month loot box purchasing was significantly related to gambling problems in bivariate analyses. When including age, gender and past-month monetary gambling, loot box purchases were still associated with at-risk and problem gambling in both samples. As expected, these other predictors attenuated the predictive value of recent loot box purchases in relation to gambling problems. The odds-ratios, nevertheless, were still in the predicted direction and remained significant. When controlling for monetary gambling, age and gender, recent loot box purchasing increased the odds of problem gambling 3.7 to 6.0 times, and at-risk gambling 2.8 to 4.3 times. Discussion and conclusions: While causal relationships between loot box purchasing and problem gambling remain unclear, the results indicate that loot boxes disproportionately attract adolescents experiencing gambling problems, adding to the financial stress already caused by gambling. Consumer protection measures, youth and parental education, and age restrictions on loot box games are needed to protect young people.  Kulcsszavak: gambling, gambling disorder, loot box, video games, youth