Intra-Industry international trade refers to the process of importing and exporting similar goods and services belonging to one industry between different countries (Brülhart, 2009). The essence and causes of intra-industry trade are the subject of much discussion as this process contradicts the traditional frameworks of trade as well as the principle of comparative advantage. This deviation from the classical patterns can be explained by exchange rates and differentiation of products and services. In addition, imperfect market structure also rates among the major factors in the shift of patterns (Cabral & Silva, 2006). Thus, the paper at hand offers to provide an analysis of intra-industry international trade in connection to imperfect market structure. It will define and investigate economies of scale, monopolistic competitions, the gravity model of trade, global oligopolies (strategic trade policy), and agglomeration economies (external economies of scale) using examples. The analysis will end with a case study with the aim of giving a closer look at theoretical materials that could help draw a precise and accurate conclusion. Economies of Scale Economies of scale are supposed to be achieved if the manufacturer manages to produce more units of goods or/and services at a greater scale with lower input costs. Thus, the result can be identified as a cost advantage that appears with the higher output of a product (Clark, 2010). This implies that when a company grows and increases production, it receives more opportunities to reduce its input costs as they are distributed between larger amounts of products. Variable costs per unit are also likely to be reduced due to operational efficiency. Such economies are divided into two major types: 1) internal economies of scale (that appear within the organization); 2) external economies of scale (emerging as a result of some extrinsic factors such as the size of the industry). When economies of scale are realized in a lot of different industries, economic growth is said to be achieved (Cabral & Silva, 2006). Industries featuring a low level of scale economies generally have quite high intra-industry trade shares. This happens for several reasons (Clark, 2010):   * Economies of scale are restricted to organizations that are monopolistically competitive and manufacture differentiated goods. To ensure that several companies coexist within one industry, economies of scale will become exhausted at low output levels. When this happens, the average costs may remain unchanged—changes in output will not affect per unit costs. Therefore, low-scale economies result in more companies within one industry, the outputs of which go into trade.   * There is also evidence that scale economies are captured within branches of industry that have huge organizations characterized by reduction of costs with the increase of size. Such companies usually produce standardized goods (metals, chemicals, etc.) that are involved in inter-industry trade rather than in intra-industry trade. Thus, scale economies are captured due to a low variety of products, which allows concluding that a negative association exists between the economies of scale and intra-industry trade.   * Industries with low-scale economies are expected to have rather high levels of intra-industry trade also due to their vertical specialization. The point is that vertical