ABSTRACT Magnetoelastic materials are amorphous, ferromagnetic alloys that usually include a combination of iron, nickel, molybdenum and boron. Magnetoelastic biosensors are mass sensitive devices comprised of a magnetoelastic material that serves as the transducer and bacteriophage as the bio-recognition element. By applying a time varying magnetic field, the magnetoelastic sensor thin films can be made to oscillate, with the fundamental resonant frequency of oscillations depends on the physical dimensions and properties of the material. The change in the resonance frequency of these mass based sensors can be used to evaluate the amount of analyte attached on the sensor surface. Filamentous bacteriophage specific to S. typhimurium was used as a bio-recognition element in order to ensure specific and selective binding of bacteria onto the sensor surface. The sensitivity of magnetoelastic materials is known to be dependent on the physical dimensions of the material. An increase in sensitivity from 159Hz/decade for a 2mm sensor to 770Hz/decade for a 1mm sensor and 1100Hz/decade for a 500micron sensor was observed. The sensors were characterized by scanning electron microscopy (SEM) analysis assayed biosensors to provide visual verification of frequency responses and an insight into the characteristics of the distribution of phage on the sensor surface. The magnetoelastic sensors immobilized with filamentous phage are suitable for specific and selective detection of target analyte in different media. Certain modifications to the measurement circuit resulted in better signal to noise ratios for sensors with smaller dimensions (L<1mm). This was achieved by tuning the circuit resonance close to that of the sensor. According to models and preliminary tests, this method was anticipated in about a 5 times increase in signals for a 200×40×6microns. This technique and further studies into the design and modification of the measurement circuits could yield better, sensitive responses for sensors with smaller dimensions. The magnetoelastic materials offer further advantages of potential miniaturization, contact-less nature and ease of operation.