The adoption of herbicide-tolerant soybeans (HTS) in Argentina was a very rapid process, as HTS covered virtually all of the area under soybean cultivation less than 10 years after their introduction in 1996. In our analysis, we focus on the patterns of HTS adoption. Using a survey-based analysis, we compare early and late adopters in the subdivisions of Pergamino and Salto (in the northeast of the Argentinean province of Buenos Aires) with regard to their expectations related to HTS adoption, as well as the characteristics of the farm and farmers. Moreover, we analyze the role of seed companies in the adoption and diffusion processes. This study shows that the expectations of cost reduction and easier crop management were the main drivers for farmers in the adoption of HTS. Furthermore, our results suggest that seed companies played a major role in providing farmers with their first information on HTS and their role has been influential for the farmers’ adoption decisions.