A menu driven computer program has been developed for Nonlinear analysis of plane framed structures. This program utilizes the stiffness method. Only material nonlinearity has been considered. A full screen editor facilitates the input and editing of data. The input data are stored for changes to the original structure. Individual files are created for each of the data categories and are stored in ASCII format. A method of plastic analysis of plane frames taking the interaction of bending moments (M) and axial force (P) into account has been developed. A yield curve on the M-P space of the form f(M,P)=O is assumed.