This study sought to investigate Internet fraud among Business to Consumer e-commerce operators and customers in Dar es Salaam, Tanzania. The study specifically examined the extent of using e-commerce among customers and operators. It also examined the level of awareness about internet fraud, the extent of experienced internet fraud and factors influencing internet fraud among customers and operators during engagement in e-commerce activities. The study population comprised B2C customers who had access to the internet from five wards of Ilala Municipal and e-commerce operators from different areas of Dar es Salaam. Data were collected through a questionnaire survey of 400 B2C customers in Ilala Municipal with a return rate of 80%. A total of nine key informants from e-commerce operators around Dar es Salaam were also interviewed. The Unified theory of acceptance and use of technology (UTAUT2) was utilized in the study. The results revealed that all 268 surveyed respondents were engaged in different categories of e-commerce. They were mostly engaged in paying for several services that are offered by ecommerce operators followed by those who were engaged in reading news through ecommerce applications. Other B2C e-commerce categories were socializing, content followers, buying physical products and promotions also registered a reasonably high number of customers. Through interviews, it was also revealed that e-commerce operators had registered an increased number of users of their e-commerce activities and applications. Meanwhile, levels of awareness about internet fraud among customers and operators are low, because of the lack of knowledge to recognize and respond to various fraudulent activities. The findings also confirm that operators and customers lost money and products as a result of their participation in e-commerce activities. Through this study it was not possible to reveal the extent of the loss incurred, because respondents and key informants were not willing to disclose. It was xvi also revealed that there were serious problems with mobile money services, as both ecommerce operators and customers expressed. At multivariate analysis, it was discovered that among the factors influencing behavioural intention were performance expectancy, social influence, hedonic motivation, perceived risk and awareness. The study also found that social influence, awareness, facilitating conditions and behavioural intention were significant factors in influencing customers use behaviour of e-commerce applications. Further, there was no statistically significant relationship between both e-commerce use and behavioural intention and internet fraud. At the Chi-Square test, the study found that the level of awareness about internet fraud and use behaviour was influenced by level of education. Those who are educated showed high level of awareness for their engagement in online shopping compared to their counterparts. In the same manner, level of education influenced the use behaviour of e-commerce activities. The findings conclude that e-commerce activities are becoming more important to Dar es Salaam residents due to its benefits and convenient and hence increase in users of e-commerce applications. However, more efforts are required to raise awareness of internet fraud, benefits of e-commerce and the negative impact of internet fraud are of profound importance. Therefore, this study recommends that the government, e-commerce operators and other business stakeholders should work together to improve e-commerce activities, specifically on payment mechanisms. On the same way, law enforcement authority should take stern actions against fraudsters, specifically to mobile money services as it had been revealed to be a serious problem.