The global recession circumstances, cloud computing has emerged as a new paradigm in the business IT sector. This paper focuses on Software as a Service (SaaS) among cloud services. The Technology Acceptance Model (TAM) has been popularly utilized for examining how users come to accept a new technology, but have not yet been employed to handle issues regarding SaaS adoption. This paper aims at developing an exploratory model that examines important factors affecting SaaS adoption of small and medium sized companies. The proposed exploratory model tests a number of hypotheses which integrate TAM related theories with additional imperative constructs such as marketing effort. Thus, the findings of this study can not only help company users gain insights into SaaS adoption, but also help SaaS providers obtain inspiration in their efforts to discover more effective courses of action for developing their service and improving marketing strategy.