In open channels broad crested weirs are widely used to measure the discharge values. In this study the effect of the approach angle on the discharge efficiency of the broad crested weir was investigated experimentally. Four different approach angles were tested under steady state conditions by using three different discharge values. Experimental results indicate that the discharge coefficient is not only a function of crest length but also a function of approach angle. A modified new non dimensional empirical relation involved approach angle has been proposed.