Abstract: This study addresses a very important topic in corporate finance that is not well treated in many developing stock markets with particular reference to Nigeria. Beta is a major component of the Capital Asset Pricing Model (CAPM) used in the determination of the required rate of return on equity but a very high percentage of the documented works done in this area have been out mostly in developed economies cum stock markets of America, Europe and Asia. However, since we have need for stock market, there is also need to estimate equity betas which will be used to determine the required rate of return on equities traded in our markets in order to guide investors in making investment decisions. Based on this need we calculated the (historical) betas of the listed stocks in the brewery sector of the Nigerian Stock Exchange from 2000-2012, a 13 years period. From the estimation of beta for the listed stocks, it was discovered that on the average, Guinness has the highest beta risk content of 11.05% closely followed by Nigerian brewery with 10.39% while International brewery has the highest alpha risk content of 96.63% closely followed by Jos International brewery with 90.38% in the brewery sector of the Nigerian Stock Exchange (NSE). On the average, the systematic risk content in the brewery sector stocks is <4%. Therefore, the bulk of the risk in this sector is constituted by unsystematic idiosyncratic non-market determined specific diversifiable risk.