Dubach, U. C, P. S. Levy (National Center for Health Statistics, Rockville, Md, 20852), and A. Müller. Relationships between regular analgesic intake and urorenal disorders in a working female population of Switzerland. I. Initial results (1968). Amer J Epidem 93: 425–434, 1971.—As a first phase of a long-term longitudinal study, a population of 7, 311 women aged 30–49 years, employed In 88 establishments in Northwest Switzerland, was screened for evidence of regular intake of phenacetin containing analgesics. From this, a Study Group of 623 women showing evidence of such intake and a Control Group of 621 women showing no such evidence were established. As a second phase, each individual was interviewed and examined for proteinuria, hematuria, bacteriuria, elevated serum creatinine, low specific gravity (post thirst), and abnormal kidney size. The Study Group showed higher prevalences of proteinuria, low specific gravity and history of kidney disorders. As a third phase, both groups will be followed for evaluation of the risk from regular analgesic intake of subsequent development of urorenal disorders.