Resistivity, SP and Gravity measurement was conducted in order to delineate an arsenic contaminated area in peninsular Thailand. Low resistivity of 25 to 100 Ohm.m and positive SP anomaly of 60 mV were observed in area where arsenic contents in auger water at 3.5 to 5.0 m depths was high, 0.5 to 5.0 mg/l. In addition subsurface rise explained by high resistivity and positive gravity anomaly probably acted as a buried dam separating high contaminated area in the west from the low contaminated in the east of the study area. JICA, 1999. Draft final report on the environmental management planning survey for arsenic contaminated area of the Nakhon Si Thummarat Province in the Kingdom of Thailand