The paper examined the price relationship between cotton and polyester. The results provide strong evidence of long term price transmissions and granger causality between cotton and polyester price as well as the asymmetry transmissions for cotton on cotton, cotton on polyester, and polyester on polyester price. However, we did not find any evidence that there exists asymmetry transmission for polyester price on cotton price. Our results also did not support the contemporaneous effects hypothesis between polyester price and cotton price.