Exploratory drilling in Oklahoma, exclusive of the Panhandle, decreased 15 percent from 1962 while development drilling remained unchanged; in all 3,405 wells of both types were drilled. Successes have increased from 58.3 percent in 1959 to 69.4 percent in 1963; new-field wildcats in 1963 were 22.2 percent successful. Distribution of all 1963 discoveries, in every Paleozoic system, are graphically shown by rock unit and by geologic province. Forty-two percent were in the Anadarko basin and its northeastern and eastern shelf areas, including 30 new fields; Mississippian limestones are the principal reservoir rocks. Ten new gas fields were found in the Arkoma basin in 1963. Oklahoma's oil and gas production was up over 1962, 1 percent and 2 percent respectively. A brief summary of the geologic history of Oklahoma is included, and a simplified correlation chart.