A hollow core slab is a precast prestressed concrete member with longitudinal hollow cores that reduce its self-weight. This paper presents the effects of openings on flexural and shear behavior of precast prestressed hollow core slabs. Three full-scale hollow core slabs of dimensions 4100x1200x160 mm were tested. One slab without opening is considered as a control specimen. The second slab with a central opening with dimensions 250x250 mm at mid of span was tested to investigate the effect of this opening on the flexure capacity. The third slab has an opening at mid of one-third of span was tested to investigate the effect of the opening on shear capacity of hollow core slab. All specimens were tested under four loading points until failure. Test results showed that the opening at mid-span decreases the flexure capacity of the slab. The failure load of the slab in this case is decreased by about 11.40%. The failure modes of the hollow core slab with a central opening as well as the control slab were ductile. The presence of the opening at maximum shear affect the slab behavior badly. It caused a sudden failure. The reduction of the failure load was about 21%