Measurement of cutaneous delayed-type hypersensitivity (DTH) to a battery of ubiquitous antigens is an accepted means of assessing cell-mediated immunity (CMI). The recently introduced Multitest CMI system consists of a plastic multiple puncture device that simultaneously applies seven standardized recall antigens in a reproducible manner. A representative population of 448 healthy US schoolchildren was tested to determine incidence and size of DTH responses to each of the seven antigens. All responded to one or more antigens, the number and size of reactions generally increasing with age. Incidence of positive DTH tests was highest for tetanus and diphtheria toxoids, intermediate for streptococcal, Candida, and Proteus antigens, and lowest for tuberculin and Trichophyton antigens. These normal values, related to age and sex, can be a foundation for immunologic evaluation and are the basis of a proposed scoring system that distinguishes between normal DTH reactivity and diminished responsiveness.