Abstract: The effect of geometric parameters of the shell and thp stiffener, as well as the shell laminate configuration on the buckling and initial postbuckling behavior of stringer or ring stiffancd laminate circular cylinders is analysed. The initial postbuckling analysis is based on Koiter's general theory.The calculations for various geometric parameters and shell laminate and loading configurations show that in every case,outside stiffening is more efficient than inside stiffening;the stiffening efficiency of composite cylinders is higher than their isotropic counterparts; the buckling and initial postbuckling behavior is influenced significantly by the shell laminate configuration.