This paper describes a fluorescence biosensor based on a microfluidic device where an organic LED is used as light emitting source. The device was able to detect fluorescence from a 0.012 mul volume chamber containing 3 ng of donkey anti-sheep IgG (Immunoglobulin G) conjugates tagged with Alexafluor 488 fluorophores. The minimum detectable concentration of the antibody was identified at an enzyme concentration of 200 mug/mL. This result shows that organic LED sources can be used as emitter/photodetector pairs to test biological samples. Based on our results, a multipurpose, integrated biological sensor that can identify and measure the concentration of fluorophore substances is dicussed..