The synapsins are a family of proteins whose function as regulators of synaptic vesicle cycling has been thoroughly investigated in neurons. Previous work had demonstrated the presence and functional role of synapsin I in sperm, but focused primarily on human sperm and did not investigate other synapsin proteins. The rationale/hypothesis of this study was to investigate the presence of synapsins I, II, and III in mouse sperm, as the confirmed presence of the synapsin proteins in mouse sperm specifically would allow for various functional investigations more easily performed using rodent models. This hypothesis was tested using manually applied dot blot analysis of mouse testis/epididymis (T/ E) and separate mouse sperm samples. The hypothesis was supported, as the dot blot results indicated the presence of synapsins I, II, and III in both the mouse T/E and sperm cell samples. This preliminary but important positive result sets the stage for future functional experiments which may include sperm motility assays, as well as in vitro fertilization studies following treatment with synapsin antibodies. These studies would add to the existing body of knowledge concerning the molecular regulation of cellular secretion, as well as the mechanisms of fertilization and reproduction.