The relatively recent increase both in number and in gravity of the skin conditions known as dermatophytosis and dermatophytid has arrested the attention of the medical profession in general and that of the dermatologist in particular. Should the present trend continue, it is possible that the evolution of this malady may bring about a grave condition of affairs. One hesitates to predict the situation that may arise should the severe cases, fortunately only occasionally observed, become the rule. The choice of the subject of the present symposium witnesses that this section is aware of the importance of this problem. It is time to marshal our forces to the combat, and a discussion of some of the immunologic aspects of the disease cannot be amiss. In addition to a brief review of previous work, we intend to report some more recent aspects and as yet unpublished observations in this field. While