Rainfall interception losses were monitored for 12 months and related to vegetation and rainfall characteristics at the Wanariset Sangai on the upper reaches of Mentaya river. The rainfall interception losses were quantified based on the records of 55 selected rainfall events in the unlogged forest and of 95 rainfall events in the logged-over area. In the unlogged forest, the total amount of rainfall interception loss was 251 mm or about 11% while in the logged forest, it was 219 mm or 6%. It was also simulated by the Gash’s original and revised models. Both models adequately predicted total interception loss over a long period, resulting in estimates of the interception loss deviated by 6-14% for both forests.