There has been an increasing interest in the area of electronic invoicing and more and more organisations send their invoices electronically. Today it is mostly large organisations and the public sector that utilise e- invoicing. Small and medium sized enterprises (SMEs) have not adopted e- invoicing to the same extent, even though new, simpler and more affordable techniques for e-invoicing have been introduced. The purpose of this study was to gain a better understanding of the adoption of electronic invoicing in SMEs, by describing the factors that affect the adoption of electronic invoicing in SMEs and how adoption of electronic invoicing can be facilitated. In order to provide understanding of the subject, case studies of three SMEs were made. The SMEs studied were: NKV, J. Petterssons Chark and BD Fisk. The findings of this thesis indicate that there are several factors that affect adoption of e-invoicing in SMEs. Pressure from customers is considered to be an important factor for e-invoicing adoption in SMEs. Furthermore, the SMEs perceive that adoption of e-invoicing can be beneficial, and lead to increased internal efficiency as well as impact on business processes and relationships. The innovativeness of the owner/manager was also found to influence adoption of e-invoicing. The results from this study also indicate that technologically, the SMEs are ready for an adoption of e-invoicing and in general the SMEs in the study also have enough financial resources to adopt e-invoicing. However, technological and financial assistance and coercive methods are considered to facilitate adoption of e-invoicing in SMEs.