Molecular biology is increasingly affecting all areas of clinical medicine, including pediatric critical care medicine. Recent advances in genomics will allow for a more in-depth understanding of disease processes that are relevant to the pediatric intensivist, such as sepsis, the acute respiratory distress syndrome, and multiple organ dysfunction syndrome. In turn, understanding critical illness at the genomic level may allow for more effective stratification of patient subclasses and targeted, patient-specific therapy. The related fields of pharmacogenomics and pharmacogenetics hold the promise of improved drug development and the tailoring of drug therapy based on the individual's drug metabolism profile. Therapeutic strategies aimed at modulating host inflammatory responses remain viable but will need to take into account the inherent redundancy of the host inflammatory response and the heterogenous responses between individual patients. Thus, "immuno-phenotyping" of critically ill patients will allow for more rational immune-modulating therapies, either in the form of inhibiting or enhancing specific immune/inflammatory responses. The host also contains powerful, broad cytoprotective mechanisms that could potentially be harnessed as a strategy for organ and tissue protection in many forms of critical illness. Finally, prospects for gene therapy, although quite challenging at present, may be applicable to the intensive care unit in the near future. With these rapid advancements in molecular biology, it is imperative that all pediatric critical care practitioners become, at least, familiar with the field and its related technology. Hopefully, clinician-scientists involved in pediatric critical care will also shape the direction of these future prospects.