We present a novel homogeneous (mix-incubate-read) droplet microfluidic assay for specific protein detection in picoliter volumes by fluorescence polarization (FP), for the first time demonstrating the use of FP in a droplet microfluidic assay. Using an FP-based assay we detect streptavidin concentrations as low as 500?nM and demonstrate that an FP assay allows us to distinguish droplets containing 5?mu M rabbit IgG from droplets without IgG with an accuracy of 95%, levels relevant for hybridoma screening. This adds to the repertoire of droplet assay techniques a direct protein detection method which can be performed entirely inside droplets without the need for labeling of the analyte molecules.