It is of great importance that the drilling program required for the newly drilled wells is estimated by using the drilling data of the previously drilled wells in a field or basin to complete the drilling under economic and optimum conditions within the estimated time. In this study, in the Southeastern Anatolia and Thrace basins of Turkey, where both oil and gas exploration and production are performed, a new approach has been presented for the estimation of drilling time before drilling, using the rate of penetrations (ROPs), weights on bit (WOB), rotation speeds, and actual (net) drilling times of the previously drilled wells as well as based on the formation thicknesses predicted by the geological and geophysical data provided from any field. For the formations in both basins, equations for the actual drilling time estimation and drillability factors have been determined depending on them. The results of the new approach show that the actual drilling times can be estimated with high accuracy according to the formation thickness to be drilled before drilling. Moreover, ROPs can be forecasted based on the estimated actual drilling times.