An analytical model for dynamic response analysis of low‐rise steel frame buildings on microcomputers is described. The model consists of an assemblage of planar frames with either braced or moment resisting connections. All but the frame lateral degrees of freedom are removed using static condensation prior to assemblage of the overall model. Floor diaphragms are modeled as either flexible or completely rigid in their own planes. Linear elastic behavior is assumed in the model and time‐history dynamic analysis is performed using the mode‐acceleration method. A FORTRAN computer program was written to implement the model on a microcomputer and a sample analysis of an actual building is presented to illustrate its use. The program was envisioned as a simplified analysis and design tool which could aid a designer in investigating a proposed structure or in rehabilitating an existing one for lateral f