Internet addiction is currently considered a worldwide problem, with a possible impact on mental health. This study aimed to investigate the prevalence of internet gaming disorder (IGD) among Italian young adults and to explore its association with psychopathological symptoms. Our sample included 566 young adults (324 males/242 females; age: 22.74 ± 4.83 years). Participants were asked to state their favorite games and complete the following questionnaires: the Internet Gaming Disorder Scale Short Form (IGD9-SF); the APA symptom checklist, based on DSM-5 diagnostic criteria for IGD; the Symptom Checklist-90 Revised (SCL-90 R); and the Social Adaptation Self Evaluation Scale (SASS). Use of video games was common among study participants (95% of the sample). Thirty subjects (5.3% of the sample) matched criteria for a clinical diagnosis of IGD. Data showed a positive correlation between higher use of online games and higher levels of depression (r = 0.501), anxiety (r = 0.361) and psychoticism (r = 0.431), and lower family and extra-family relationships (r = -0.383). At linear regression analysis, somatization ( = 0.002), depression ( = 0.001) and sleep disturbances ( = 0.003) were predictors of IGD diagnosis. IGD was significantly associated to mental health distress. Healthcare professionals should be aware of the problematic consequences of online gaming.