Purpose: The authors evaluated the clinical results and prognosis after amputating the lower extremity due to diabetic foot. Materials and Methods: From 1991 to 2003, the patients who had suffered amputation of his lower extremity due to diabetic foot ulcer were evaluated retrospectively. 79 patients were male and 6 patients were female. The author evaluated the patient who had the ipsilateral additional surgery, contralateral amputation, level of blood sugar, combined disease and mortality rate within 5 years from medical record. Statistical analysis was done by Chi-square test and Kaplan-Meier survival test. Results: Mean age of patients who had first experienced amputation was 63.4 years old. The mean duration of diabetes until amputation was $14.5{pm}7.5$ years. Major amputations were 50 cases and minor amputations 35 cases. 20 patients (23.5%) were suffered ipsilateral secondary surgery including revised stump. Overall 5-year mortality rate was 18.8% (16 cases). Death rate within 1 year was 8.2% (7 cases), mortality rate within 3 years was 14.1% (12 cases). 5-year mortality rate after major amputation was 20% (10 cases) and after minor amputation was 17.1% (6 cases). It was statistically significant (p<0.05). Patient who underwent more than 2 combined vascular related disease had higher mortality rate than diabetic amputee without combined disease (p<0.05). Conclusion: Mortality rate after major amputation was significant higher than amputation after minor amputation in diabetic patients from our data.