In this study, we examine the effect of TRIPS on the relationship between R&D expenditures and patent applications in manufacturing firms. The first set of tests examines the association between patent applications and R&D expenditures and firm specific factors such as firm size and capital intensity. The next set of tests adds environmental factors including R&D intensity of the industry and development of TRIPS. We divide the sample period into three subperiods according to the progress of TRIPS subperiod 1(1984-1988) before TRIPS, subperiod 2(1989-1994) after negotiation of TRIPS and subperiod 3(1995-2000) after agreement on TRIPS. Regression model reveals that the coefficient on firm size is significantly positive over the all sample Period, while that of R&D expenditures of R&D intensive firms is significantly positive in subperiod 2 and 3(1989-2000) and that of capital intensity is significantly negative only in subperiod 3(1995-2000). The findings suggest that the efficient intellectual property system promotes the patent application of R&D intensive firms.