This paper investigated intrinsic motivation as a mediating factor of the relationship between CEO characteristics and accounting information system adoption in the SMEs of Libya. The adoption model with mediation was tested with a sample of 348 top level managers and owners of SMEs. Understanding the main determinants of accounting information system adoption for SMEs is very crucial, whereas characteristics of CEO play a significant role in identifying users' behavioural intention for technology adoption. For this purpose, structural equation modelling approach was applied using quantitative research design. Findings supported intrinsic motivation as partially mediating between CEO's characteristics and users' behavioural intention. Therefore, motivating users intrinsically by providing knowledge, innovativeness and trust will have an effect on Accounting information system (AIS) implementation in the organisational context.