PURPOSE: The purpose of this study was to analyze the results of treatment and prognosis of Marjolin's ulcer compared with primary squamous cell carcinoma. MATERIALS AND METHODS: Fourteen patients treated for Marjolin's ulcer were analyzed. Twenty patients with primary squamous cell carcinoma treated during the same time period was the control group. Mean age was 61.2 years. There were 24 males and 10 females. The locations, TNM stages, histological grades, recurrence, metastasis, and survival rate were analyzed and compared between two groups. RESULTS: The mean follow-up period was 54.8 months (range, 12-168 months). Local recurrences were found in 6 cases, 5 ones in Marjolin's ulcer patients, and one case in primary squamous cell carcinoma patients. The mean time interval between the initial presentation and occurrence of local recurrences was 9 months (range, 2-20 months). There were 6 metastases. 2 (14.3%) metastases were found in Marjolin's ulcer patients, and 4 (20.0%) metastases in primary squamous cell carcinoma patients. Total events (metastasis or local recurrence) were found in 10 pateients, 6 of them in Marjolin's ulcer group, and the remaining four in primary group. 5-year disease-free survival rate was 64.3% in Marjolin's ulcer group and 95.0% in primary squamous cell carcinoma group. CONCLUSION: Squamous cell carcinomas originating as Marjolin's ulcers revealed higher recurrence rate and lower survival rate despite of aggressive treatment. Therefore, new treatment modalities should be developed for improving outcomes.