Zeolite FAU was heated directly by microwave irradiation at 2450 MHz in an open system without special loading materials. It was discovered that zeolite X was heated to 1473 K about 90 seconds at power output of 400 W. HY type zeolite was also heated to 1373 K although it needed relative long time (about 11 minutes). Influences of exchangeable cations and adsorbed substances on zeolite1s ability to absorb microwaves were also discussed.