Interferon-inducible transmembrane protein (IFITM) family proteins are antivirus factors. In the present study, we examined the expression pattern of chicken IFITM10 using quantitative reverse transcription-polymerase chain reaction. In adult chickens, IFITM10 levels were markedly lower than those of IFITM3, which exhibits antivirus activity. On the other hand, IFITM10 was expressed in levels similar to those of IFITM3 in embryonic organs. Primordial germ cells in 2.5-d embryos expressed high levels of IFITM10, which gradually decreased with time. The interferon- stimulation of embryonic fibroblast cells did not enhance the expression of IFITM10. The forced expression of IFITM10 slightly inhibited the infectivity of the VSV-G-pseudotyped lentiviral vector. Furthermore, cell fusion was inhibited by IFITM10 when HeLa cells transfected with the VSV-G expression vector were treated with low pH buffer. Although it remains unclear whether IFITM10 inhibits viral infections under physiological conditions, these results suggest that chicken IFITM10 exhibits antivirus activity.