A novel feline paramyxovirus, Feline Morbillivirus (FeMV, a.k.a. FeMV), was first discovered by RTPCR in 2011 in 12.3% (56/457) of urine, rectal swabs, and blood samples from stray domestic cats (Felis catus) in China. This discovery associated FeMV with tubuloinsterstitial nephritis (TIN), as TIN was present in a significantly higher proportion of cats with FeMV than in cats without FeMV (P< 0.05). Further identification of similar viral sequences in Japan in 2013, in Germany in 2015, and in the USA in 2016 provided evidence that these viruses are widely spread and likely associated with TIN. Paramyxoviral genomes consist of the typical six-gene arrangement: N-P/V/C-M-F-H-L. The typical role of the matrix protein (M) is virion assembly at the plasma membrane. The fusion protein (F) executes fusion of viral and cellular membranes during viral entry or the pathognomonic cell-cell fusion, upon receptor binding and signaling from the attachment glycoprotein H, HN, or G. FeMV sequence alignments placed FeMV viruses within the Morbillivirus genus in the family Paramyxoviridae. Since little is known about the emerging FeMV viruses, the knowledge gaps are vast.