Background: Disturbance of balance and falls are commonly observed in people with multiple sclerosis (MS). Objectives: The aim of this study is to assess the postural balance in patients with MS by using clinical and instrumental methods and to specify the most direction of balance instability among MS patients using Biodex stability system (BSS). Methods: Fifty ambulatory individuals with MS [42 relapsing-remitting (RRMS) and 8 secondary progressive (SPMS)] were evaluated for balance using quantitative Berg balance scale (BBS) and BSS. Twenty healthy volunteers were selected as a control group. Results: There was a statistically significant difference between the patient and control groups assessed by BBS. Moreover, patients with SPMS had worse postural balance when compared with RRMS. According to BSS, MS group showed more sway in the three limits of stability (mediolateral, antroposterior, and overall) when compared to the control group. The least stability level was observed in mediolateral direction in the patient group. The degree of tilt was higher in SPMS than RRMS as regard the three limits of stability. The BBS was significantly negatively correlated with age, Expanded Disability Status Scale (EDSS), duration of illness, and the Biodex tilt. Also, there were positive significant correlation between age, EDSS score, and the duration of illness of the disease with parameters of BSS (mediolateral, antroposterior, and overall). Conclusion: BSS was significantly correlated with clinical balance measurement scale using BBS in MS patients. Moreover, BSS can provide more objective, quantitative measures of postural imbalance.