The production of petroleum in western Europe in 1966 decreased 3 percent from 1965. Natural gas production increased greatly. A 1966 North Sea discovery has gas reserves of 6 Tcf in lower Permian sandstone. A deep oil discovery in Mesozoic limestone, and oil and gas discoveries in Miocene sandstones were reported from the Vienna basin (Austria). French exploration decreased except along the Pyrenees frontal zone. Two gas discoveries occurred in Germany, one of which is high in nitrogen. Significant extensions were made in the Po basin (Italy). Exploration decreased in the Netherlands. Gas was discovered in Friesland. Spain had two minor oil discoveries and a gas discovery. Oil was discovered in the Drava valley in Yugoslavia. A 1965 gas discovery near London (England) was developed. Soviet Union production increased to more than 5 million barrels of oil and 14 Bcf of gas daily. A large pipeline from Siberia to European Russia and possibly Italy is planned. Individual country reports are included.