On the occasion of the 450th anniversary of Philipp University, the porphyrin research group of. the Department of Clinical Biochemistry in the Faculty of Medicine organized an international symposium. This was held between June 28 and July 1, 1977, under the joint chairman ship of Professor Samuel Schwartz and the editor. The organizers and chairmen of the symposium wish to thank the Sozialminister of Hessen, Armin Clauss, the President of the German Society for Clinical Chemis try, Professor A. Delbrlick, and the Dean of the Faculty of Medicine of Philipp University, Professor F. Neurath, for their support and patronage. We are also grateful to Professor A. Treibs of the Institute of Organic Chemistry, Technical University of Munich. Professor Treibs, a former pupil, co-worker and now successor to the Nobel laureate Hans Fischer, kindly accepted the honorary presidency of this international symposium. The opening ceremony was inaugurated by the chairmen, with welcoming speeches by the President of Philipps University, Mr. Rudolf Zingel and patrons of the university. The editor outlined the 10 years of development of clinical biochemistry at Philipp University and traced in detail the continual development of its chief research effort in porphyria. It was pointed out that following the first international symposium on the regulation of porphyrin and heme biosynthesis in 1973 at Marburg (Doss, M. (ed. ): Regulation of Porphyrin and Heme Biosyn thesis."