The developmentally arrested life stage of the entomopathogenic nematode Steinernema feltiae is exposed to threats of survival, including desiccation. We adopted a comprehensive approach to the study of the molecular mechanisms of desiccation stress tolerance in S. feltiae IS-6. We identified, expressed sequence tags (ESTs) that are differentially expressed during desiccation stress in S. feltiae IS-6 infective juveniles using DNA subtractive hybridization. These ESTs included genes that are known to be stress related, genes that are homologous to hypothetical Caenorhabditis elegans proteins, and novel genes that may be involved in traits specific to S. feltiae. Expression pattern characterization revealed that all analyzed ESTs were induced during 8 and 24 hr of dehydration of S. feltiae IS-6. Our results unveiled some of the components of the genetic networks that are activated in S. feltiae IS-6 during dehydration and suggested a differing pattern of temporal regulation during nematode dehydration.