Abstract: The invention relates to a crematorium oven 1 comprising at least one combustion chamber 2 with a ceiling, wall 2.1 and base 3 on which to place the object to be cremated, a heat supply system 4, a combustion air supply 5 and a flue gas outlet 6. Within the ceiling and/or the wall 2.1 and/or the base 3 of the combustion chamber 2 at least one combustion air supply channel 7 and at least one flue gas return channel 8 are provided whereby the flue gas return channel 8 in the ceiling, and/or the wall 2.1 and/or the base 3 has an inlet 8.1 and an outlet 8.2. In the ceiling and/or wall 2.1 and/or in the base 3 of the combustion chamber 2 the at least one combustion air supply channel 7 opens into the at least one flue gas return channel 8, so that with the supplied combustion air a suction effect of the combustion air supply into the combustion chamber 2 is brought about. In this way at least part of the flue gas produced during the combustion process is drawn into the inlet 8.