Changes of the porosity and density of various metals and alloys due to the formation and development of micropores and microcracks in the process of high-temperature creep are studied in numerous experiments. Based on these studies the density is considered as integral measure of the structural micro-defects accumulation, and the damage parameter is defined as the ratio of current density to initial density. Taking into account this parameter and the mass conservation law interconnected kinetic equations for creep deformation and damage parameter are formulated. An analytical solution connecting the damage parameter to the value of deformation is obtained. In this case, the creep deformation is calculated approximately. The comparison of theoretical damage and creep curves with corresponding experimental data are given.