In this paper an innovative micromachined passive flow regulator for implantable drug delivery systems is presented. The aim is to passively achieve a constant flow rate over a certain pressure range through linear variation of a flow resistance. This flow regulator is based on bending membrane contact with a micromachined substrate. A first serie of samples has been realized using standard Silicon micromachining. For better biochemical performances, a second version of the device has been manufactured in Titanium using a combination of micromachining and conventional machining. Test results show a DI water flow regulation of 6 nanoliters per second over a pressure range between 100 mbar and 600 mbar.