The purpose of this paper is to investigate the degree of intra-industry trade in the Pacific Basin which includes developing countries as well as advanced countries. The Aquino index, with slight rearrangement for aggregation over countries and correction for trade imbalance, is chosen as the measurement. The findings are that the major hypotheses about the intra-industry trade which are believed to be applicable mainly to advanced countries could also be applicable to developing countries. Industries with high capital intensity, high degree of product differentiation, and large economics of scale, show high degree of intra-industry trade in the Pacific Basin. [420]