Abstract: A recording spirometer for performing both a single breath test and a maximum voluntary ventilation test. The spirometer includes a housing in which is disposed a pusher plate. This pusher plate is supported by a member constrained by rotary bearings to move in substantially a straight line. An elastomeric seal creates an airtight chamber beneath the pusher plate. The supporting member also carries a recording medium support so that a permanent record may be made of the volume of exhaled air as a function of time. For performing the maximum voluntary ventilation test, the apparatus includes a mechanism for supporting the pusher plate at an intermediate position so that both inhalation and exhalation segments may be measured and recorded. A rotatable turret is provided for carrying a plurality of pens for marking the recording medium so that different colors may be used for different tests.