Given the increasingly aging population, nearly every doctor will encounter elderly adults who present with multiple complex comorbidities that can challenge even experienced physicians. This may explain why many medical students do not have a positive attitude toward elderly adults and find the complexity of their problems overwhelming. It was hypothesized that a recently developed medical school geriatrics course, based on the game GeriatriX and designed specifically to address the complexities associated with decision-making in geriatrics, can have a positive effect on attitudes toward geriatrics and on perceived knowledge of geriatrics. The effects of this game-based course were evaluated as a proof of concept. The assessment was based on the Aging Semantic Differential (ASD) and a validated self-perceived knowledge scale of geriatric topics. The usability of (and satisfaction with) GeriatriX was also assessed using a 5-point Likert scale. After completion of the course, the ASD changed significantly in the geriatrics course group (n = 29; P = .02) but not in a control group that took a neuroscience course (n = 24; P = .30). Moreover, the geriatrics course group had a significant increase in self-perceived knowledge for 12 of the 18 topics (P = .002), whereas in the control group self-perceived knowledge increased significantly for one topic only (sensory impairment) (P = .04). Finally, the geriatrics students reported enjoying GeriatriX. This proof-of-concept study clearly supports the hypothesis that a 4-week course using a modern educational approach such as GeriatriX can improve students' self-perceived knowledge of geriatrics and their attitudes toward elderly adults.