Consumers today are using various channels to complete their purchase process. As shoppers pursue different goals at each stage of the process, channel choice may be explained by different drivers for search, purchase and post-sales activities. Our research framework is based on an extension of the TAM Model with the support of the Motivational Model, differentiating two types of motivations for channel usage: intrinsic and extrinsic. Moreover, we rely on transaction costs economics to explain different channel usage at each shopping stages and for different product categories. Lineal regression and cluster analysis are applied to data collected through a survey answered by 1,533 multichannel retail shoppers within two product categories (apparel and consumer electronics) in two countries (UK and Spain). Our findings show that segments with different usage patterns and motivations can be identified across the shopping process and that the drivers of channel usage are different depending on the stage of the buying process and the product category considered.