Purpose : To compare and analyze the results of arthroscopic subacromial decompression and rotator cuff repair between partial rotator cuff tear and complete rotator cuff tear. Material and Methods : The authors studied 42 patients of rotator cuff tear with operation and followed over one year at Dankook university hospital from September, 1998 to March, 2001 The patient average age is 53 years and follow up period is 23 months (12-42mon1hs). We obtained 22 cases in the partial rotator cuff tear group and 20 cases in the complete rotator cuff tear group. In all cases, we used ASES methods to evaluated pain scale and function. Result : In the last follow up patients, the pain scale is decreased from 7.2 to 0.9 (ASES method : 34 to 91) in the partial rotator cuff tear group and from 7.6 to 1.2 (ASES method . 29 to 88) in the complete rotator cuff tear group, but there was no evidence of statistical difference between two groups (P>0.05). The range of motion after operation were increased in two groups. Excellent to good results were obtained 93％ and 95％ patients had pain relief and satisfied function. Conclusion : Arthroscopic subacromial decompression and arthroscopic rotator cuff repair showed good results for both of (ult-thickness and partial thickness rotator cuff tear patients in pain relief and improving the function.