Numerous ex-ante and ex-post studies have been conducted to assess the impact of the abolition of Agreement on Textiles and Clothing (ATC) on textiles and clothing (T&C) exports. The purpose of the present study is to examine how the dismantling of ATC, which may have led to lower trade cost due to economies of scale, has influenced the two margins of trade, product-intensive and product-extensive margins, for regional competitors in South-Asia, i.e. Pakistan, India and Bangladesh (P.I.B) in its two major destination markets, the EU and the USA. This is achieved by decomposing total export growth in T&C into product-intensive and extensive margins, and determining which of the two margins has been dominant for South Asian T&C exporters. The implications arising from the study may be useful in policy analysis for T&C sector aimed at diversification in sectoral exports, and may also aid in identifying and effectively targeting sub-sectors in T&C. The assessment is also carried out at sub-sectoral level, Textiles (HS Chapters 50 to 60), and Clothing (HS Chapters 61 to 63). To define trade margins, the study utilizes the definition employed by Kehoe and Ruhl (2013). Their study uses country variant cut-off trade value to classify traded goods into old products (product-intensive) and new/least-traded products (product-extensive). They argue that non-traded goods should be defined taking into account the size of countries. Since sizes of countries differ, the relative importance of the goods they trade also differs. This technique eliminates the invariant cut-off limitation that biases small countries toward export concentration. This study employs this definition only for the pre-ATC period (2003-05). First, the average exports of 695 T&C product lines in pre-ATC period (2003-05) were arranged in ascending order. For each exporter, the products that comprised only 5% of total average exports were then filtered and identified as new/least-traded lines. The remaining products were identified as old product lines. An augmented gravity equation is estimated separately for total T&C exports, product-intensive and product-extensive T&C exports, at the sectoral and sub-sectoral levels, and for combined destination markets (EU and USA), and then for separately for each destination market, using three estimating techniques: Pooled OLS, Fixed Effect and Tobit models. The following main findings emerge after an empirical exercise:- It shows the effect of effect of quota removal via ATC dismantling is mainly on the extensive margin rather than the intensive margin. Generally, as fixed trade costs are reduced, a large variation in trade flows is explained by the extensive margin relative to the intensive margin. Our analysis hence confirms the result that abolition of quotas reduce the exporters’ costs and increases diversification, while reduction in tariffs reduces variable costs and has a greater impact on the intensive margin than the extensive margin. Quota abolition created opportunities for South Asian exporters in the two developed destinations markets but at the same time exposed them to tougher competition from exporters such as China. For China, the abolition of quota served as a disincentive to diversify, while South Asian exporters looked toward diversification as a survival strategy. Another important finding is the one-off gains for new exporters during the time was that not only were quotas abolished via ATC integration, but new, small, and less productive exporters were able to enter the markets since safeguards were imposed on imports of Chinese T&C by EU and USA. This impact overrides the ATC abolition impact on extensive margin of trade. Another important finding that also has theoretical backing is that preferential market access affects both the margins positively. However, at the product level, and specifically for the EU market, the tariff preference margin had a greater impact on the intensive margin than the extensive margin. Due to lower variable costs (tariff reduction), the incumbent firms are able to increase their revenues, while the new exporters with lower productivities face not only high fixed costs, but also higher variable costs compared to incumbent firms. Additionally, tariff preferential margin has led to increased exports at the intensive margin because preferences are mostly negotiated product by product. An important implication of this finding is that preference margins play an important role in increasing T&C exports to the EU but has little impact on export diversification. Trade preference margin is more important to export profitability in the EU market due to its generous preferential scheme, while China quota is more definitive in the US market since South Asian exporters compete with Chinese products with slight cost differences, and greater export similarity. The extensive and intensive margins of T&C exports vary considerably across destination countries. Because there are differentiated impacts of policies on sectoral exports, sub-sectoral exports and their margins in the two markets, this indicates that policy-makers and marketing strategists fine-tune their exporting policies and marketing strategies for different markets. The impacts of quota removal and safeguard measures imposition are more distinct for textiles than for clothing. Protectionist measures undertaken by governments of developing countries may have become a deterrent in the way of firms’ investments in efficient technologies, so that they failed to upgrade production to better quality products within the same sub-sector, and hence botched to tap destination market niches.