The concentration method of volatile organic compounds in tap water by using Amberlite XAD-4 resin was developed for GC-MS analysis. Averages of elution recovery of six kinds of chlorinated hydrocarbons by using ether from the XAD-4 resin (20-50 mesh) column (500×8 mm) were 92% and 84% at high concentration levels (2.35-6.40 mg/l) and low concentration levels (0.32-1650μg/l), respectively. This extraction method was applied to real water samples. Volatile compounds were eluted into a glass minivial with 14 ml of ether after passing 200 l of tap water through the XAD-4 resin column. The ether was evaporated and concentrated to 1 ml by using a stream (200 ml/min) of clean nitrogen gas under cooling by dry ice. Volatile compounds were separated with PEG 6000 or OV-17 GC column and analyzed by GC-MS. As a result, various organic compounds such as trihalomethanes and volatile hydrocarbons were found in tap water.