Magnetoelastic resonance biosensors were fabricated by immobilizing a bio-molecular recognition element onto the surface of Fe79B21 magnetoelastic particles (MEP). These sensors can be measured wirelessly and remotely for both in-air and in-liquid bacteria detection. Filamentous bacterio-phage that was selected specifically for the detection of Bacillus anthracis spores was employed as the biomolecular recognition element and immobilized onto the MEPs' surfaces. Attachment of the spores to the sensor surface due to specific phage-spore binding results in a shift in the resonance frequency of the biosensor. Insitu measurement of the resonance frequency of biosensors of 5×100×500 microns were used to determine the sensor response as a function of spore concentrations of 103 to 108 cfu/ml. Specificity of the sensor was evaluated by conducting tests using a mixture of Bacillus anthracis Sterne strain, Bacillus cereus and Bacillus megaterium spores.