An empirical method is presented for predicting the crippling stress at L/p < 20 of 24S-T Alclad bent-up sheet stiffeners, 24S-RT Alclad bent-up sheet stiffeners, and 24S-T extruded stiffeners acting alone or in conjunction with 24S-T Alclad sheet as a panel. I t is also shown tha t predicted column curves maybe constructed by drawing a straight line tangent to the Euler column curve (c = 1.5) through the predicted crippling stress at L/p = 20 (except through L/p = 40 for extrusion stiffened panels); the predicted stress a t L/p = 20 (or 40) locates the horizontal cutoff for the section of the column curve with L/p < 20 (or 40). The general method, which consists of summing the crippling loads of the component elements of the stiffener and then dividing by the summation of the elemental areas to obtain the crippling stress, is discussed in several texts on airplane structural analysis; however, enough test data have not been available heretofore to establish general empirical curves for predicting the Strength of any stiffener or stiffened panel of reasonable proportions.