Enhanced understanding of host-pathogen interactions at local sites of infection will extend our knowledge of disease pathogenesis and will facilitate the development of novel preventive methodologies against many infectious diseases of economic importance. In the current study, a 9.6K avian intestinal intraepithelial lymphocyte cDNA microarray (AVIELA) was developed to compare the local transcriptional profiles following primary and secondary infections with two major Eimeria parasites, E. acervulina (EA) and E. maxima (EM), which infect the intestinal duodenum and jejunum, respectively. Gene Ontology analyses showed that EAinfection primarily induced genes associated with lipid metabolism and intracellulartrafficking whereas EM infection upregulated the genes involved in protein biosynthesis and metabolism, and downregulated apoptosis related genes. Following primary EA infection, there was a significantly enhanced expression of genes involved in the signal pathway of T cell activation and cytoskeletal regulation. Thus, the AVIELA array provides a valuable tool for investigating host-pathogen interactions in avian coccidiosis and allows for the comparison of the transcriptional regulations induced by species of Eimeria that infect different areas of the intestine.