Abstract: An immunochromatographic strip was developed for the detection of the H9 subtype of avian influenza viruses (H9AIVs) in poultry using McAb 4C4 for H9AIV hemagglutinin and chicken anti-AIV antibody. The 4C4 was labeled with colloidal gold as a detection reagent, and chicken anti-AIV antibody was blotted on the test line while a goat anti-mouse antibody was used on the control line of the nitrocellulose membrane. In comparison with the hemagglutination (HA) and hemagglutination inhibition (HI) test, the strip was specific for detecting H9AIV with the sensitivity at 0.25 HA units within 10 min. Storage of the strips at room temperature for six months or at 4 ℃ for 12 months had not changed their sensitivity and specificity. 311 tracheal samples from potentially infected chickens were detected using the strip and ELISA kit established in our lab, the coincidence ratio was 92%. Further characterization of 10 positive samples randomly selected showed that no single sample was false positive, as determined by the HI assays and standard virus isolation. Our research revealed that the immunochromatographic strip for detection of H9AIVs has high specificity, sensitivity and stability. This, together with the advantages of rapid detection and easy operation without requirement for special skills and equipments, makes it suitable for the on-site detection and differentiation of H9AIVs from other viruses in poultry.