AbstractSpirometry is the most commonly used pulmonary function test. The aim of this comparative study was to evaluate four commercially available spirometers with different measurement principles (turbine-, ultrasound-, differential pressure- and hot-wire anemometer). In particular, the measurement accuracy in breathing manoeuvres with low flow rates was investigated, which is highly relevant for paediatric use. Among the tested devices the hot-wire based spirometer showed the highest measurement accuracy at low flows whilst fully complying with the ATS/ERS standards.