OBJECTIVE: The purpose of this study is to evaluate the therapeutic effect and clinical applicability of 5% sodium morrhuate sclerotherapy as primary surgical approach in cases of mucous systs. MATERIAL & METHODS: 15 cases of mucous cysts who were treated with 5% sodium morrhuate sclerotherapy were evaluated and 11 cases were followed up during 1994's. First, mucous cyst was incised, and washed out several times. 5% sodium morrhuate was infused slowly(More than 5 minutes) and throughly for maximal contact. Pressure dressing was done with elastic bandage for 2-3 days. RESULTS: Age of patients were distributed form 12 year-old to 44 year-old. Involved sites were wrist97), thumb(2), ear(1), and hand(1). 5 cases among 11 cases(45%) were cured completely, but 6 cases(55%) were reoccurred, Timing of recurrences were distributed from 2-3 days till 4 months, and mean was 40 days. Patients assessed the satisfactions of therapy as excellent 2, good 1, fair 1, poor 7. complications were mild pain, hardening, and pigmentary change. CONCLUSION: 5% sodium morrhuate sclerotherapy might be useful as a primary surgical approach in cases of mucous systs because of simplicity. It is expected that therapeutic effects of sclerotherapy would be improved by repeated applications, changing to more potent sclerosants and meticulous pressure method.