In the construction of modern buildings many pipes and ducts are necessary to accommodate essentially services like (water supply, swage, air condition, electricity, telephone and computer network).To pass these ducts through transverse openings in the floor Prestressed concrete beams, some parameters must be studied to know the effect of these parameters on the strength and on the toughness of the Prestressed concrete beams, these parameters were the size and location of the openings and shear span of the tested beams. So ten beams were prepared and tested {two beams without openings (as a guide beams) and eight (8) beams with openings (with different openings dimensioning, different locations and different shear span)}.The tested of all the rectangular beams were carried out and the results were recorded and we noticed that, the strength of Prestressed concrete beams increase with decrease the size of the openings and with increase the shear span, (the toughness*) of the Prestressed concrete beams increase with increase the size of the openings and with the decrease of shear span.