In 1936 Mazar started the excavations of Beth Shearim, the first archaeological excavation organized by a Jewish institution, and uncovered there the large Jewish catacombs dated to the 2nd-4th centuries CE, known as the burial place of the Jewish leader Rabbi Yehudah Hanasi, the compiler of the Mishnah. In 1948 he was the first archaeologist to receive a permit to dig in the new State of Israel, and explored the Philistine town of Tell Qasile in northern Tel Aviv. He later conducted excavations at Ein Gedi and between 1968 and 1978 directed the excavations south and south-west of the Temple Mount in Jerusalem, including an area he described as the Ophel, uncovering extensive remains from the Iron Age through the Second Temple period and to Jerusalem's Islamic period.