A combined analytical and experimental investigation of the stability of composite cylindrical shells is presented. Forty-five fiber-glass filament wound cylinders were fabricated, buckled, and analyzed. The number 45 stems from considering three diameters (6 in, 12 in, 24 in), three filament configurations, and five loadings. All cylinders had essentially the same wall thickness, .035 in, and each cylinder length was nearly equal to its diameter. The five loadings were: (1) uniform axial compression, (2) torsion, (3) bending, (4)combined torsion and uniform axial compression, (5) combined bending and uniform axial compression. The analysis was based on linear anisotropic shell theory and the effects of boundary conditions were not considered. Preliminary tests were conducted to determine the in-plane stiffnesses and individual layer elastic properties. The experimental buckling loads were from 67 to 90% of predicted values for loading without torsion. The bending buckling stress was, for all practical purposes, equal to the axial buckling stress and the combined bending with uniform axial load interaction was essentially linear. The experimental torsion buckling loads were greater than the predicted values but the boundary conditions were not considered in the analysis. Buckling loads were computed for boron filament wound cylinders of the same size and winding configurations. These computations show that the buckling loads of boron and aluminum cylinders, of the same size, are nearly equal. A similar comparison on a weight basis would produce the same result since their densities are essentially equal.