Shear strength of a reinforced concrete (RC) member should be larger than its flexural strength, in order to prevent the shear failure, which is sudden and brittle. The reliability of a RC beam against the shear failure is closely related to the reliability of the equation determin-ing its shear strength. In this study, the reliabilities of shear strength equations of RC beams were investigated by constructing the performance function between prediction equations and experimental results using a second-moment approach. It is assumed that the random variables are statistically independent, and the correlation effects are not taken into account. It is observed from the reliability rankings that the equation of EN 1992:2004 yields the lowest failure probability while the equation of Zsutty is the highest failure probability.