Initial Public Offers (IPOs) attract much attention in World stock markets. The IPOs do not go unnoticed in emerging markets since they are focal points, particularly if listed alone, and stirs the whole market. As such a single large IPO can have a significant effect in a less developed market. Therefore, this study sought to evaluate the effects that IPO announcements had on the market return of listed stocks at the Nairobi Stock Exchange(NSE). In addition, the study assessed the effects of the turnover and volume traded on the market return. The study incorporated all the seven recently floated IPOs at the NSE between January 2006 and March 2009. The main results from the fitted linear regression model showed that all IPOs had a significant effect on the market return. In particular, Co-operative Bank, KenGen, and Volume traded had a negative effect while the remaining IPOs, elections and turnover had a positive impact on the market returns. This will be a source of valuable information to the capital Markets Authority, Nairobi Stock Exchange as well as investors for decision making, legal and Policy formulation.