Liquid and gaseous products are recovered from oil shale in an in situ oil shale retort in which a combustion zone is advanced therethrough by a method which includes the steps of establishing a combustion zone in the oil shale in the in situ oil shale retort and introducing a gaseous feed mixture into the combustion zone in the direction the combustion zone is to be advanced through the in situ oil shale retort. The gaseous feed mixture comprises an oxygen supplying gas and water vapor and is introduced into the combustion zone at a rate sufficient to maintain the temperature in the combustion zone within a predetermined range of temperatures above the retorting temperature of the oil shale in the in situ oil shale retort and sufficient to advance the combustion zone through the in situ oil shale retort. The introduction of the gaseous feed mixture into the combustion zone generates combustion products gases which together with the portion of the gaseous feed mixture which does not take part in the combustion process, is called flue gas. The flue gas passes through the oil shale on the advancing side of the combustion zone, thereby retorting the oil shale to produce liquid and gaseous products. The liquid product and the retort off gas, which comprises gaseous product and flue gas, are withdrawn from the in situ oil shale retort at a point on the advancing side of the retorting zone.