The Heckscher-Ohlin (HO) model regarde as a modern theory of trade, dominant for more than a quarter of a century had to face more and more challenges in the second half of the 20th century. It seemed that the 2*2*2 (product-factor-country) model, which assumed perfect competition, constant return to scale and homgeneous products and whose elegance was rooted in its simplicity, could not offer appropriate answers for the explanation of empirical facts in two significant areas. The conclusion of the model, namely that countries will have a comparatvie advantage in the productions of goods for which they use factors of production relatively abundant in the country, was first questioned by the Leontief paradox and later by the empirical facts of intraindustrial trade. The study focuses on this latter phenomenon. In the first part it presents and classifies the major theoretical models of the phenomenon, and in the second it discusses, on the basis of empirical surveys in this field, the most important factors influencing intraindustrial trade.