Olfactory sensory organ can perceive the chemical molecules of external environment. Here, we observed olfactory and vomeronasal organs in Pelophylax nigromaculatus using the silver staining, nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) histochemistry staining and electron microscopy. Three cell types in the olfactory and vomeronasal epithelia could be distinguished using silver staining. Nuclear staining of supporting cells was strongly dark, but nuclear staining of the receptor cell was in a irregular spotting pattern. In addition, the proportion of olfactory receptor cells in the vomeronasal epithelium was significantly more than that of the olfactory epithelium. The olfactory and vomeronasal organs showed different staining patterns and they could be easily distinguished when NADPH-d histochemistry staining was employed. Finally, the supporting cells in the olfactory and vomeronasal epithelia consisted of two cell types: ciliated supporting cells and granular secretory supporting cells.