Over the last decades, Virtual Reality (VR) emerged as a potential tool for developing new rehabilitation treatments in neurological patients. However, despite the increasing number of studies, a clear comprehension about the impact of immersive VR-treatment on balance and posture is still scarce. In this study, we aimed to investigate the postural alterations in post-stroke patients and elderly people during the exposure to an immersive moving virtual scenario. Ten patients with sub-acute stroke and ten healthy subjects took part in this study. Both groups were immersed in a CAVE system on a baropodometric platform. The VR task consisted in ten trials, which differed in term of speed and movement direction. Results showed that the sway path length (representative of the body sway amplitudes) was trial-dependent for both groups. Therefore, the kind of virtual visual stimulation influenced the body sway response and it could be considered for designing a rehabilitation protocol.