Barriers to e-commerce adoption in small to medium enterprises (SMEs) have been widely researched and documented. This paper adds to the existing research in two ways. Firstly, it proposes that the sources of e- commerce adoption barriers can be found in the features that are unique to SMEs, in contrast to their larger counterparts. Secondly, it analyses the correlation between the adoption barriers using data collected from more than 300 SMEs in Sweden. The results of this analysis indicate that correlations between the barriers do exist and that the barriers can be grouped according to two distinct factors: the difficulty of implementing e- commerce and the unsuitability of e-commerce to the business.