A mathematical model previously derived by Golden, et al, (1973) is developed and extended to allow for the simulation of a wide range of pulmonary function tests. The model parameters include large airway resistance, small airway resistance, collapsible airway resistance, collapsible airway compliance, and lung compliance. And, the model is driven by a varible pleural pressure waveform. The simulation is implemented on an analog computer for ease of parameter manipulation. The effects of changes in model parameters on selected pulmonary function tests are observed and discussed. Simulations of diseased states (emphysema, asthma, and fibrosis) are presented and analyzed. It is concluded that the model properly simulates breathing maneuvers associated with the clinical assessment of pulmonary function. In addition the model structure is much simpler than the ventillatory system models of Fry (1968) and Pardaens, et al, (1972), yet yields the same information in a diagnostic sense.