Avian influenza virus (AIV) has caused serious epidemics all over the world. Notably, the low-pathogenic AIV H9N2 has been spreading widely, leading to enormous economic losses to the poultry industry. To rapidly monitor airborne H9 AIVs in chicken houses, a real-time RT-PCR method was established and used to detect virus in air samples, and it was also compared with the traditional RT-PCR. The results showed that the real-time RT-PCR possessed high specificity and sensitivity for H9 AIVs, and the sensitivity reached 100 copies/reaction, much higher than the traditional RT-PCR; airborne H9 AIVs were found in the six chicken houses by real-time RT-PCR, and their mean concentrations ranged from 1.25×10(4) to 6.92×10(4) copies/m(3) air. Overall, the real-time PCR is a valuable tool for detecting airborne H9 AIVs.