Introduction: With the introduction of Begg’s, technique there isopening up of deep anterior overbite by depressing both upper and lower anterior teeth in their sockets. The aim of the study was to evaluate the efficacy of bite Opening by the Begg technique during the first stage of treatment cephalometrically. Materials and Methods: Materials for the study consisted of thirty pre-treatment and end of stage 1 cephalograms taken of patients treated with Begg mechanics. Tracing of the radiographs of Class I, Class II division 1 and Class II subdivision malocclusion cases were made and reference planes were drawn. The difference between the pre-treatment and stage-I measurements for all the sixteen parameters were analysed statistically. The student paired t-test was applied to determine the level of significance. Results: The estimation of apparent bite opening due to lower incisor proclination was derived using correlation coefficient and the regression equation was estimated. Overbite is reduced markedly with a mean of 4.66 +/- 1.637 mm, which is statistically highly significant. The result showed an apparent bite opening with a mean value of 1.97+2.44 mm which is statistically highly significant. Conclusion: Overbite was reduced markedly in all the cases with this technique used by Begg’s and mandibular incisors showed a marked amount of intrusion, which accounts for 63.6% of bite opening which is found to be the primary factor contributing to correction of deep overbites.