Soviet and foreign literature data on scabies morbidity structure in families and organized collective bodies are reviewed. The authors' own data include an analysis of 88 clinical and epidemiological charts, developed and filled in by the authors. The notion of the disease focus in scabies is introduced for the first time. The foci are divided into potential (with an only patient) and irradiating ones (with two and more patients). Organized collective bodies predominate among the potential foci (85.7%), whereas families prevail among the irradiating foci (80.7%). The incidence rate of the condition in a focus depends not on the focus size, but on the time and intensity of the contacts of the patients with healthy subjects.