A flowmeter and filter assembly for spirometry comprises a flowmeter (B) with a turbine rotor (R) and sensor means for detecting the speed of rotation of the rotor, and a filter (C) upstream of the flowmeter (B). An air-conveying device (DC) modifies the direction of the flow of air at outlet from the filter (C) to set the rotor (R) in rotation within the flowmeter (B). Said air-conveying device (DC) is integrated in the filter (C) instead of in the flowmeter (B).
