DNA microarray platforms represent a functional genomics technology that uses structured information obtained from genomic sequencing efforts as a means to study transcriptional processes in a systematic and high-throughput manner. Specifically in this chapter, we outline the ordered processes involved in large-scale parasite gene expression studies including complementary (cDNA) microarray fabrication, total RNA isolation, cDNA labeling using fluorochromes, and DNA:DNA hybridization. Methods described herein were adapted for the study of schistosome sexual maturation and developmental biology but could be easily modified for the study of any additional parasitological system.