Radiative heat transfer between surfaces separated by transparent medium is discussed in this paper. The method of net heat-flux equations suggested here is an extension of Poljak method which had been discussed in details by Jakob. By directly applying known condtions it may be used to solve unknowns such as net heat-flux in heat transfering surfaces and temperatures in refractory surfaces. All surfaces must be diffusie emitters and reflectors but need not be gray and refractory surfaces are not necessarily restricted to a single one or adiabatic. In comparison with methods recently suggested by Hottel et al[ 6 ]and Sparrow et al. [ 3 ] deduction and use of the present method are somewhat easier. Formulas derived from this method are the same as those printed in texts[1-5] for simple cases and numerical solution is easier for the complex cases which is illustrated with an example. The effect of subdivision of refractory surface and of non-homogeneity of surface temperature is also discussed.