Background People with Parkinson`s disease (PD) often suffer from both motor and cognitive impairments. Simultaneous motor and cognitive training stimulates neurobiological processes which are important especially for people with PD. The aim of this study is to test the feasibility and effects of simultaneous cognitive–motor training in form of exergames in the setting of inpatient rehabilitation of persons with PD. Methods Forty participants (72.4 ± 9.54 years; Hoehn and Yahr stage 1–4) were randomly assigned to either the intervention group, which trained five times a week in addition to the conventional rehabilitation program, or the control group, which underwent the standard rehabilitation treatment only. Primary outcome was feasibility (measured by adherence rate, attrition rate, occurrence of adverse events, system usability scale (SUS), and NASA TLX score). In addition, various cognitive (Go/No-Go test, reaction time test (RTT), color word interference test (D-KEFS) and Trail Making Test A and B (TMT)) and motor (preferred gait speed, maximum gait speed, dual-task gait speed, Short Physical Performance Battery (SPPB), Timed Up and Go (TUG) and 5 times Sit-to-Stand (5xStS)) tests were conducted before and after the intervention phase in order to determine training effects Results Adherence rate was 97%, there were just two dropouts due to reasons unrelated to the study and there were no adverse events. The mean NASA TLX value was 56.2 and the mean value of the SUS was 76.7. Significant time–group interaction effects were observed for the 5xStS, the SPPB, the RTT, the Go/No-Go test and the D-KEFS 2. Discussion Exergaming, as applied in this study, showed to be feasible, safe and likely effective for the improvement of cognitive and motor functions of PD inpatients. Because of this future randomized controlled trials with a main focus on testing the efficacy of this new intervention are warranted. Trial registration: The study has been registered at ClinicalTrials.gov (ID: NCT04872153).