Abstract: The present invention provides an intravenous fluid flow regulator 10 for controlling the I.V. administration of medical fluid to a patient. The fluid flow regulator 10 provides a housing 12 having a top 18 and a bottom 20. A flexible diaphragm 14 is positioned within housing 12. A diaphragm holder 16 is provided inside housing 12 for holding a sealing edge 56 of flexible diaphragm 14 in fluid sealing engagement with diaphragm holder 16. The housing 12 and flexible diaphragm 14 define an inlet fluid reservoir 62 and an outlet fluid reservoir 64. The diaphragm holder 16 defines a by-pass fluid channel 54 from inlet fluid reservoir 62, around diaphragm 14, to outlet fluid reservoir 64. The flexible diaphragm 14 being flexible to alternatively move into inlet fluid reservoir 62 and outlet fluid reservoir 64 depending on a fluid pressure differential between inlet fluid reservoir 62 and outlet fluid reservoir 64. A fluid inlet 24 is connected to housing top 18 to provide an inlet fluid passage 27 from an I.V.