This paper describes the synthesis of mixed proteinaceous microspheres (MPMs) by the sonochemical method. The current fundamental research follows the research of Suslick and co-workers who have developed a method by which high-intensity ultrasound is used to make aqueous suspensions of proteinaceous microcapsules filled with water-insoluble liquids.1 By using high-intensity ultrasound, we have synthesized microspheres made of a few different proteins. The three proteins used in the current experiments are bovine serum albumin (BSA), green fluorescent protein (GFP), and cyan fluorescent protein-glucose binding protein-yellow fluorescent fused protein (CFP-GBP-YFP). The two synthesized microspheres made of mixed proteins are BSA-GFP and BSA-(CFP-GBP-YFP). This paper presents the characterization of the sonochemically produced microspheres of mixed proteins. It also provides an estimate of the efficiency of the sonochemical process in converting the native proteins to microspheres.