The objective of this work was to develop oils of maximum radiation stability from readily available ingredients. Lubricants in three viscosity grades were made with alkylbenzenes containing selected polymers and additives. Each new oil was subjected to standard tests to determine if it met the specifications for presently used products made from mineral oils. The special oils complied with most requirements, and shortcomings were generally correctable. Both the special and conventional oils were irradiated under water in the Canal Gamma Source at the Materials Testing Reactor (MTR) in Idaho. Most conventional oils were damaged beyond usefulness at 10×108roentgens (r). The alkylbenzene fluids still retained lubricating qualities after 50 to 70×108r and remained fluid well above 100×108r. These results prove the feasibility of making radiation resistant lubricants by this new approach.Presented as an American Society of Lubrication Engineers paper at the Lubrication Conference held in Los Angeles, Calif., October 1958.