ABSTRACT In this work we present a new analytical model of cyclic steam injection, which integrates conventional energy balances with solutions of the equations of flow in radial geometry to predict process performance during the production period. The fluid flow in the hot zone is given in terms of the clasical solution of radial flow for steady state conditions. The pressure in the outer boundary of the hot zone, however, varies with time according to the movement of crude oil in the cold zone, as given by a transient solution of the equation of flow for a liquid of slight compressibility in an infinite radial aquifer. In the model we include time translations as well as effective compressibilities to take into account the effect on reservoir pressure of volume of fluid injected during the injection cycle and production mechanisms such as compaction. We used the model to perform sensitivity studies for a typical heavy oil reservoir in the Bolivar Coast of Lake Maracaibo in Western Venezuela, varying volume of injected steam, number of cycles, lenght of production period and other reservoir characteristic parameters. In all cases the model qualitatively described the characteristic behavior of the process, observed at the field level. From a quantitative point of view, the equations presented in this work gave results of incremental oil production within 17 % of the observed production response of a well located in the Monagas State in Easter Venezuela, after it had been steam stimulated for three cycles. Likewise, for a well m the Lagunillas formation of the Bachaquero field in Western Venezuela, predicted results after four steam cycles came witin 30 % of actual production.