The extent to which the clinical recognition of the condition termed cystic fibrosis of the pancreas has progressed, as well as the limitations of this term, are revealed in a study of 105 patients from a single clinic, followed from 5 to 14 years. The authors have devised a somewhat complicated scheme for evaluation of the clinical condition of patients with this disease and the effects of therapy. When a truly satisfactory treatment is available we shall probably not need a complicated scheme to appraise the results. Here once again it may be seen that some patients with this disease may survive for long periods without the benefit of medical care or regardless of the therapy they may have received. Ten patients in the series had reached the age of 15 years or over at the time of the report; in 7 of these the diagnosis was not established until the age of 8 years or over. However, the authors point out that the duration of life prior to diagnosis may not be a measure of the severity of the disease. That the prognosis has improved is indicated by the finding that prior to 1948 the average age at death was 12 months, and during the period from 1951 through 1956 the average age at death was 59 months. The authors realize that the prognosis is largely dependent upon the course and severity of the pulmonary involvement. One of the principle mysteries in this disease is the variability in the effect of the fundamental process on the various susceptible organs.