Studies on primary atypical pneumonia, especially those of the past four years, have resulted in the awareness of a rather well defined clinical picture in this disease. Several authors, however, have presented series of cases differing considerably in their symptomatology. It is the purpose of this paper to describe a group of cases of the disease appearing during the first half of 1944 in Italy and to compare them with cases previously reported. A large number of the patients were evacuated from Anzio, and, in a sense, the outbreak may be regarded as localized. This series consists of 45 patients whose uniformity of symptoms is especially interesting as a form which the disease may take. Conditions governing the evacuation of casualties render it virtually impossible for one to reach any conclusions concerning epidemiology. It is my impression from conversation with patients that successive groups of persons in particular units were