Purpose: This study evaluated the results of conservative treatment for simple bone cyst. Materials and Methods: We studied 126 cases of simple bone cyst, which were treated by observation or steroid injection from February 1990 to May 2010. Their mean age at diagnosis was 14 years (${pm}9$ years, 2-60 years) and the mean follow-up duration for this study were 41 months (${pm}37$ months, 12-159 months). Observation and steroid injection was applied for conservative management of simple bone cyst and results was scored by modified Neer classification. Results: 31 cases (24.6%) were treated by observation and 95 cases (75.4%) were treated by steroid injection. The 95 patients were treated by a mean of 1.1 (${pm}0.9$, 0-4) steroid injections and a single steroid injection was given in 65 cases (51.6%). The 102 cases (80.9%) were resulted in modified Neer classification I and II which could be considered as healing of simple bone cyst. Conclusion: Conservative management can be considered as an initial treatment for simple bone cyst with good result.