Background: Robotic mechanotherapy is considered as a promising area of physical rehabilitation of multiple sclerosis patients, while it ensures high training efficacy. Aim: To study the effect of physical training using with the ExoAtlet exoskeleton for lower extremities the functioning of patients with multiple sclerosis. Materials and methods: This was a prospective, open, uncontrolled, single center study. The rehabilitation course with the ExoAtlet exoskeleton included 43 patients (14 male and 29 female, aged from 28 to 59 years, mean age 43,5 ± 9,12 years) with remitting multiple sclerosis in remission (RMS-R) (n = 20) and secondary progressive course (VPRS) (n = 23), with the EDSS scores from 3 to 8. One of the inclusion criteria was the presence of motor paresis of the lower extremities. Training with the ExoAtlet exoskeleton was performed 5 days a week for two weeks. The neurological deficits and functioning were assessed with the Kurtzke expanded disability status scale (EDSS), the multiple sclerosis functional composite (MSFC) test, including the assessment of walking (Timed 25 Footwalk), of upper limb functions (9-Hole PegTest, 9-HPT), and of mental functioning (Symbol Digit Modalities Test, SDMT) before and after the rehabilitation course. Cognitive functions were assessed by the Montreal Cognitive Assessment (MoCA) scale. Results: The rehabilitation course resulted in a significant decrease of neurological deficiency by EDSS (by 0.26 score, 5%, p < 0.001). The MSFC test showed an improvement in all subtests: SDMT by 2 points, or 4.9% (p = 0.018), Timed 25-Footwalk by 3.2 seconds, or 19.6% (p < 0.001), 9-HPT for the dominant hand by 1.6 seconds, or 5% (p = 0.004), and for the non-dominant hand by 2.1 seconds, or 6.2% (p = 0.006). The improvement in the MoCA test after the rehabilitation course was 1.6 points, or 6% (p < 0.001). Conclusion: The study confirmed the positive effect of the exoskeleton in the lower extremities, such as restoration of the walking function in multiple sclerosis patients. There was a positive trend towards restoring of hand motor skills and cognitive functions.