A one-way valve for medical infusion lines includes a first tubular connector and a second tubular connector, which define, respectively, an upstream passage and a downstream passage, which are coaxial and set transversely between which is a diaphragm made of elastically deformable material co-operating in a fluid-tight way with an annular seat to keep the valve normally closed. A filter, integrated in the valve, is axially clamped and blocked between the first tubular connector and the diaphragm.
