Prepared by the Reinforced Concrete Research Council of ASCE. This report reprints a collection of studies advancing the knowledge of the effects of fatigue loading on the structural behavior of prestressed concrete flexural members. Each study represents one phase of an extensive research program conducted at Lehigh University and sponsored by the Pennsylvania Department of Transportation, the Federal Highway Administration, and the Reinforced Concrete Research Council. The four areas of study are: the effect of stress gradient on the probable fatigue life of plain concrete, as related to the compression block of prestressed concrete flexural members; the probable fatigue life of seven-wire prestressing strand under repeated loading of either constant or varied magnitude; the probable fatigue life of prestressed concrete flexural members, as limited by the fatigue failure of the prestressing strand; and the susceptibility of prestressed concrete flexural members to fatigue failure in shear. This report provides guidance to structural engineers faced with the design or analysis of prestressed concrete flexural members and to research engineers who are seeking to extend the knowledge of structural behavior as affected by repeated loading.