A coupled fluid structure interaction problem is analyzed using semi-analytical finite element method involving composite cylindrical shells conveying hot fluid for free vibration and buckling behavior. The system under study is assumed to have a steady flow of hot fluid and the temperature variation is axi-symmetric. First order shear deformation theory is used to model the elastic shells of revolution. Geometric stiffness matrix is evaluated to consider the effects of axi-symmetric temperature variation through the shell continuum due to flow of hot fluid. The fluid domain is modeled using the wave equation. Numerical results of the studies on composite cylindrical shells made of HS-Graphite/Epoxy with two different length to radius ratios and clamped-clamped boundary condition conveying hot fluid are presented. The variation of the natural frequency of the coupled system is evaluated with the steady flow of the hot fluid. The influence of the temperature on the mean axial flow velocity through the shell is critically examined. The critical velocity of the hot fluid and cold fluid which leads to shell instability is compared thus establishing the fact that the lowest critical velocity of the hot fluid coincides with the mode corresponding to the lowest critical thermal buckling temperature. Various fibre angles are also considered in the study and its influence is also examined. © 2003 Elsevier Science Ltd. All rights reserved.