Former senator Dewey F. Bartlett (R-Okla.), who took pride in being ranked as one of the most conservative members of the Senate during his term, which ended in January, died of cancer Thursday in his Tulsa, Okla., home. He was 59.

He had been in poor health since January 1977, when he underwent surgery at Sloan-Kettering Memorial Cancer Center in New York for removal of a tumor from his right lung and cancerous lymph nodes from his chest.

Following discovery of new cancerous lesions on both lungs in June 1977, he announced that he would not seek reelection to a second term.

Sen. Bartlett was known as an advocate of dereglation of oil and natural gas prices to help solve the energy shortage. As a member of the Armed Services Committee, he urged the strengthening of NATO conventional foreces.

He was an opponent of increased government regulation of strip-mining, fought the Occupational Safety and Health Administration (OSHA), opposed federal land use legislation as an invasion of states' rights, and led a 1974 fight to prevent the use of federal funds to finance abortions.

In 1977, he favored a Senate bill to deregulate new sources of natural gas. He argued that this would serve as an incentive to industry to find new sources of energy, and since the price on old sources of gas would be regulated, it would not result in a marked increase in the cost of gas to the consumer.

Sen. Bartlett was a proponent of a strong military forece. Along with Sen. Sam Nunn (D-Ga.), he issued a 1976 report to the Armed Services Committee that was critical of NATO's conventional capability in the face of Warsaw Pact forces that were increasing in both quality and quantity.

The report called for an increase in conventional fire-power, larger artillery and ammunition stocks, improved air defense systems, and the positioning of forces and material closer to the Soviet border.

Sen. Bartlett also championed aid to South Vietnam and Cambodia, predicting after a February 1975 tour of Southeast Asia that a "blood bath" by Communist-led forces in both countries was assured unless they received extensive military aid.

He was a member of a congressional delegation to Somalia in July 1975, and reported that the Soviet Union had facilities for the servicing and storage of missiles carried by Soviet ships. He called for the construction of a large U.S. military base at Diego Garcia in the Indian Ocean to counter the threat.

Sen. Bartlett was born in Marietta, Ohio. He earned a bachelor's degree in geological engineering at Princeton University in 1942.

He served as a dive-bomber pilot in the Marine Corps during World War II, achieving the rank of captain.

Following the war, he entered the oil business in Oklahoma. He sold his interest in Keener Oil for what was reported to be more than $1 million and put his holdings in a blind trust following his election to the Senate in 1972.

Sen. Bartlett first became active in politics as a precinct chairman for Eisenhower during the presidential campaign of 1952. He served two terms in the Oklahoma Senate, and then was elected governor in 1966. He was the second Republican and first Catholic to hold that office in Oklahoma.

His term was marked by heavy emphasis on industrial development. He often flew to New York and other industrial centers to urge business leaders to locate their next plant in Oklahoma.

Sen. Bartlett is survived by his wife, Ann, and three children, Dewey Jr., Joan, and Michael.