Preservation of environment and natural resources has recently attracted researchers to study the use of recycled aggregates from demolished concrete in new concrete structures. This paper presents an experimental study on punching shear behavior of simply supported natural and recycled coarse aggregate concrete slabs. The punching shear behavior of interior slab–column connection in flat plates is tested in “The Reinforced Concrete Laboratory of the Faculty of Engineering, Alexandria University”. Eight two-way slab specimens using two different types of aggregate “natural and recycled” and two aggregate nominal sizes (12.5 and 25mm) were cast and tested to failure. The slabs were designed such that they would fail in punching shear only. The experimental work was conducted on (6) recycled coarse aggregate concrete (RCAC) slab specimens and (2) natural coarse aggregate concrete (NCAC) slabs. All the slabs were simply supported on four edges and tested under a central patch load. The ACI mix design procedure was adopted to achieve strength of concrete at 28days of 35MPa. Four concrete mix proportions were used with (0%, 30%, 60% and 100%) replacement of natural coarse aggregate with recycled coarse aggregate for each aggregate size. The test results showed that the first punch crack load, ultimate punch load, stiffness and energy absorption decrease as the replacement of natural coarse aggregate with recycled coarse aggregate increases. Also as the recycled aggregate size increases the cracking and failure load increases. The measured ultimate failure loads have been compared with code predictions (ECP 203, ACI 318, JSCE code, Euro code 2 and yield line theory). The Euro code – 2 equations gave the best correlation with the experimental results.