Micro-cantilever sensors have shown great promise in a wide range of application.This includes physical,chemical and biological sensing.However, many of these devices are based upon a sensor'chip'that requires careful alignment between the cantilever and the read-out system, which can be challenging.Furthermore,optical interrogation typically involves a bulky free-space system.Optical fiber addressed cantilevers have been reported previously in the literature and in this paper we propose techniques to design and fabricate onto the end of standard single mode fibers using the combination of laser micro-machining and Focused Ion Beam.Low-cost optical sources and a fiber coupled spectrometer are employed to monitor the cantilever deflection and therefore observe biological binding between a species of interest and an activated cantilever.Proof-of-concept experiments show that the sensor is capable of detecting pathogen concentration with down to a level of 104cfu/ml.