Arteriography in kidney transplantation has been recently reviewed by Weidner et al. (1). The importance of donor arteriography was stressed by these authors and is self-evident when one considers the frequency of multiple renal arteries and unsuspected renal vascular disease, either of which may eliminate potential donors. The role of arteriography in preoperative evaluation of the recipient is less clear and, in the absence of other evidence of vascular disease, is often unnecessary. Of more recent interest is the role of arteriography in assessing kidney transplants in the immediate postoperative period and during bouts of immunologic rejection (2). The development of hypertension is also seen in patients after kidney transplantation, and such patients have been included in the present study. In this series, one or more of these features were present in some part of the clinical course. An attempt to correlate these findings with the angiographic appearance of the kidney and renal biopsy material will be made. The purpose of this report is to present the findings of serial arteriograms and open renal biopsies in isograft and allograft kidneys. The arteriographic findings will be compared with those of biopsy performed at approximately the same time and with the clinical course. Autopsy findings will be included where pertinent. Materials and Methods Beginning in June 1963, a study of all kidney recipients was initiated at the Peter Bent Brigham Hospital. All new recipients were scheduled for arteriography and renal wedge biopsies, planned for 6-month intervals following transplant or as indicated by the clinical course. A study was also undertaken of previous recipients entering the hospital for re-evaluation, including identical twin recipients. The uncomplicated and stable cases were examined electively, and those whose clinical status was complicated by rejection crisis or the development of hypertension were included in the routine of the study.