Aim: Development of fiber optic vibration sensor based Spirometer. Methodology: A fiber vibration sensor is set up and is used to measure the variation of wind velocity with distance. For a source, driving air at constant speed, the variation of the light intensity level of the optical fiber sensor is studied. The experiment is repeated for various separations of source and detector fiber. The set up has also been used to measure the wind velocity. The results obtained from these preliminary studies tell the possible functioning of the sensor as a spirometer. For calibrating the fiber optic spirometer, commercially available spirometer is used. Noting down the air volume a person can inspire, from the standard spirometer, and the light intensity level at the output fiber while blowing, the spirometer can be calibrated. Results: A fibre optic vibration sensor is constructed and is used to measure the wind velocity. The set up is used as a fiber optic spirometer by calibrating it against a standard spirometer. Conclusion: The study thus reveals the application of fiber sensor as a fiber spirometer.