AN ANALYTICAL STUDY IS PRESENTED OF THE VARIATION OF THE RATIO OF CRACKING MOMENT OT ULTIMATE MOMENT IN PRESTRESSED CONCRETE BEAMS. THE EFFECT, ON THE RATIO, OF VARIATIONS IN THE SECTION PROPERTIES, THE LIMITING TENSILE STRESS OF CONCTRETE AND THE LEVEL OF PRESTRESS WERE INVESTIGATED. THE ANALYSIS SHOWS THAT THERE IS A USEFUL RANGE FOR THE STEEL RATIO AND THAT A LIMITATION IS NECESSARY FOR THE MAXIMUM AS WELL AS THE MINIMUM STEEL RATIO. IT IS ALSO SHOWN THAT A DIRECT CONTROL OF CRACKING CAN BE CARRIED OUT, BY STIPULATING A SPECIFIED VALUE FOR THE RATIO OF CRACKING MOMENT TO ULTIMATE MOMENT AND PERMISSIBLE STRESSES CAN BE DISPENSED WITH IN SO FAR AS THEY ARE INDIRECT CONTROLS OF CRACKING. /AUTHOR/