Abstract: In order to evaluate the effects of chicken granulocyte-macrophage colony stimulating factor(GM-CSF) on the anticoccidial immunity, the ORF of ChGM-CSF were cloned from chicken cecal tonsil using RT-PCR with a pair of specific primers designed from the reported sequence in GenBank. The full-length of ChGM-CSF ORF is 435 bp.The semi-quantitative RT-PCR using chicken β-actin as inner-reference for detecting the expression of ChGM-CSF was further developed and then was used for detecting the expressing patterns of ChGM-CSF in chickens vaccinated with sporulated oocysts of E.tenella at 12 and 22 day-old.Our results indicated that the expression level of ChGM-CSF in experimental group significantly increased at day 1 post-primary(P＜0.05) and day 7 post-boost(P＜0.01) infection,decreased significantly(P＜0.01)at day 9 post-primary and at day 3 post-boost infection.It is suggested that ChGM-CSF can play important roles in the immune responses against E.tenella infection in chickens.