One of the great challenge facing SMEs performance in Tanzania is how to adopt and use ICT related technologies and particularly e-commerce technology. This study examined the impediments of e-commerce adoption among Small and Medium Enterprises (SMEs) in Tanzania. Variables including poor telecommunication infrastructure, poor e-commerce security systems, lack of information technology (IT) education and training, weak government policy, high taxes imposed on e-commerce services, poor e-readiness and socio-cultural beliefs, lack of capital, lack of IT experts, abrupt technological changes and lack of clear communication standards were identified and measured using quantitative approach. An intensive literature review involving twelve (12) recent (2010-2014) related literatures was conducted to find out the impediments of e-commerce adoption among SMEs in Tanzania. Frequencies and percentages of ten (10) studied variables were computed and presented in a table and bar graph. The findings show that poor telecommunication infrastructure, poor e-commerce security systems, lack of IT education and training, poor e-readiness and socio-cultural beliefs and lack of IT experts are significant impediments of e-commerce adoption among SMEs in Tanzania. The study recommends that policy makers should view these impediments as interrelated obstacles of e-commerce adoption among SMEs in Tanzania which need integrated effort and strategies when addressing them.