The growth of Internet usage in Nigeria continues to increase, recording over 90% growth rate between 2000 and 2008. While businesses in Nigeria are reported to have online access with opportunity for e-commercial activities, customers in the country however access business websites only to source for information but make purchases the traditional way. This paper aims at assessing the prospects and challenges of Business-to-consumer (B2C) e-commerce implementation in Nigeria from the consumers’ perspective. Survey research was adopted for this study. Research hypotheses were formulated and questionnaire designed and administered randomly to 900 respondents. Collected data was used to evaluate the acceptance of B2C e-commerce using the extended technology acceptance model (TAM). The extended TAM combines task-technology fit, relationship related construct: trust and risk, and the two TAM constructs to determine factors influencing consumer acceptance of B2C e-commerce in Nigeria. Findings revealed that there are significant relationships between the model variables. Task-technology fit and perceived usefulness have significant relationships with intentions to use, having a correlation coefficient of 0.2623 and 0.2002 respectively. Similarly, the interrelationship among trust, perceived risk, and behavioral intention are significant. The effect of risk on trust was statistically showing that risk is a predictor of trust. Risk has a high significant on trust and trust in turn has low significant effect on behavioral intention. Adding TTF and its relationships to the TAM also fit the data. The relationship between task-technology fit, perceived ease of use, perceived usefulness and intention are significant. Key words: TAM, trust, risk, B2C e-commerce, consumer, internet, and task-technology fit.