In an attempt to clone some specific parasite antigen genes, a Trypanosoma cruzi cDNA library was constructed in lambda gt11. Efficient isolation of undegraded mRNA from total RNA was obtained which is a critical step for the construction of representative cDNA libraries. Lambda gtll recombinant phages were detected using isopropylthiogalactoside (IPTG) and 5-bromo-4-chloro-3-indoly1-b-d-galactopiranoside (X-gal) detection system