The paper present analysis of the stress changes due to creep in statically determinate composite steel-concrete beam. The mathematical model involves the equation of equilibrium, compatibility and constitutive relationship, i.e. and elastic law for the steel part and an integral-type creep law of Boltzmann-Volterra for the concrete part. For determining the redistribution of stresses in beam section between concrete plate and steel beam with respect to time t, Volterra integral equations of the second kind have been derived, on the basis of the theory of the viscoelastic body of Arutyunian-Trost-Bazant. Numerical method, which makes use of linear approximation of the singular kernal function in the integral equations is presented. Example with the model proposed is investigated. The creep functions is suggested by the 'CEB-FIP' models code 1990. The elastic modulus of concrete Ec(t) is assumed to be constant in time t. and Obsahuje seznam literatury