This analysis focuses on the practice of hysterectomy across 33 hospital catchment areas of one Canadian province, using claims data from the Manitoba health insurance system. Hysterectomy rates varied five-fold across hospital areas. The availability of hospitals and physicians was unrelated to area rates, and there appeared to be no access barriers in the low-rate areas. High-rate areas were characterized by women who visited large numbers of different physicians and by having larger proportions of French, Polish, and Italian residents (ethnic groups which are largely Catholic in Manitoba). Although women residents of high rate areas made somewhat more visits for gynecologic problems and had many more D&Cs (dilation and curretage of the uterus), it is concluded that this may be due as much to the practice style of physicians treating patients from these areas as to gynecologic need. Residents of high and medium-high rate areas are more likely to have hysterectomy-prone surgeons as their primary physicians. Such physicians appear both more likely to "label" their patients' conditions as gynecologic in origin and more likely to advise surgical intervention (both D&C and hysterectomy) once such conditions are diagnosed. Thus, a combination of patient and physician characteristics may explain much of the variation in small area hysterectomy rates, rather than narrowly defined medical need.