This study investigated therapeutic effects of pelvic tilt exercise (PTE) on weight bearing and body sway during sit-to-stand (STS) on 18 hemiplegic patients who had visited the Hanyang University Seoul Hospital and Injae University Sanggyebek Hospital physiotherapy rooms. The study compared the patients with 18 normal adults. The subjects were sampled out from those who could get up independently, maintain a standing posture more than 10 seconds, understand the movements of this study and have no difficulty in performing the tasks. By executing STS in a natural way with habitual movements before and after PTE, the weight bearing was measured by using Mediance II. In order to compare the difference of weight distribution, weight bearing and body sway on affected and nonaffected sides during STS before and after PTE, the Wilcoxon Signed Ranks Test was used. The statistical significance level was based on p<.05. The results revealed that the difference of weight distribution in the hemiplegic group was significantly decreased (p<.05), whereas there was no significant difference in the healthy group (p>.05). Weight bearing loaded on the affected side was $42.53{pm}7.65%$ and $44.20{pm}6.32%$, respectively, in the hemiplegic group during STS before and after PTE. Weight bearing during STS after PTE is increased significantly, as compared with weight bearing before PTE (p<.05). Body sway in the hemiplegic group was significantly decreased (p<.05). As mentioned, PTE proved to be effective for improvement in weight bearing on the affected side during STS of hemiplegic patients.