Varioloid is a term applied to a mild type of smallpox occurring in semi-immune persons who have been vaccinated successfully at a rather recent date. Lesions are discrete, not numerous, and may be scanty. Their development follows a normal course, although it may proceed at a rate faster than in the typical, extensive rash.1 Smallpox and chicken pox are closely similar diseases which not infrequently are difficult or impossible to differentiate on clinical grounds. A case of chicken pox with varioloid-like rash and laboratory confirmation of diagnosis was not found in the literature reviewed by us. Laboratory confirmation of diagnosis is seldom done in chicken pox cases because of (a) the lack of a susceptible experimental animal, (b) the natural difficulties in obtaining biopsy specimens from the patients, who usually are children, and (c) the benign character of the malady in the majority