Few of the probes described here are available as practical assays for clinical laboratories, and some have argued that currently available kits have not lived up to their promise to provide increased sensitivity, specificity, and speed of identification and detection at a reasonable cost. While these sentiments are true to some extent now, the rapid advance of techniques to enhance the rate of hybridization, to amplify the target sequences, and to label and detect hybrids nonradioactively will have a substantial impact on the availability of hybridization kits for the clinical laboratory. It is conceivable that probe technology will be simplified to the extent that it can be adapted to small laboratories, clinics, and field sites. Not only can we expect probes to speed detection and identification of established pathogens, we also look forward to perhaps the most exciting future aspect of this technology, the discovery of new agents and new infectious disease syndromes that will be brought about through its application.