Academician Prof. Dr. Isak Tadzer was born a hundred years ago on December 24, 1916 in Sofia. He completed the primary and secondary education at the German College in Sofia. In 1935 he began his studies at the Medical Faculty in Vienna, which he had to stop because of the annexation of Austria to Germany in 1938. He returned to Bulgaria where he continued his studies and graduated from the Medical Faculty in Sofia in 1941. During the War, 1941-1944, he was forcedly mobilized and he worked as a doctor in several villages. He was twice interned in camps in Bulgaria. In 1944 he joined the National Liberation Army and the Partisan Groups of Yugoslavia. After the liberation in 1945 he started specialization in internal medicine at the famous clinic of Prof. Chilov in Sofia. In 1946 he applied to the call by the Yugoslav government to the doctors in Bulgaria to come in aid of temporary work in our country. On the advice of the current Federal Minister of Public Health Dr. Dimitar Nestorov, Dr. Tadzer came to Skopje and was assigned to work in the Country hospital. He started specialization in internal medicine at the famous professor Ignjatovski, he established a family and decided to stay in Skopje. In 1949 Prof. Tadzer ended his specialization and he was elected an Assistant at the Department of Internal Medicine. In 1951 he left the Internal Clinic and he was elected an Assistant, and in 1952 he was elected a Docent in the subject of Pathological Physiology. In 1959 he was elected, and in 1964 he was re-elected as an Associate Professor, and in 1967 he was elected a Professor of pathophysiology at the Medical Faculty in Skopje. In the period from 1952 to 1978 he was Head of the Department and Director of the Institute of Pathophysiology. He was elected a Corresponding Member of the Macedonian Academy of Sciences and Arts in 1969, and a Full Member in 1974. In the period from 1984 to 1988 he was a Secretary of the Department of Medicine and Biology of the Academy. Prof. Tadzer has published over 300 scientific papers in the field of clinical medicine and pathological physiology, of which about 200 in journals in English, French, German and Serbo-Croatian, as well as 15 books, which include him among the most prolific pathophysiologists on the territory of former Yugoslavia and beyond. In the period from 1950 to 1966 several times he was on a vocational training in similar institutions and centers in Europe, and in 1972 he was on a study stay at many nuclear and medical laboratories in the USA. In addition to his great research activities his contribution as a teacher was of substantial influence and importance to the faculty. He was one of the greatest lectures at the Medical Faculty, the Faculty of Stomatology and the Pharmaceutical Faculty. Prof. Tadzer co-authored in most of the textbooks on pathophysiology for students of medicine, stomatology and pharmacy. He was an extraordinary physician, one of the pillars of the Macedonian medicine, he possessed universal, encyclopedic knowledge and is one of the most renowned medical workers in the second half of the 20th century in Macedonia. In addition to the scientific, medical and educational work Prof. Tadzer has especially rich social activity. He was President of the Faculty Council in 1975-76, he was Vice Dean of the Medical Faculty in 1958-60, Dean of the Faculty from 1963 to 1965, Dean of the Pharmaceutical Faculty and Vice Rector of the University from 1965 to 1967. Especially it should be noted his long-lasting activity at the Macedonian Medical Association of more than 50 years. Also, significant is his creative work within the Editorial board of the journal "Macedonian Medical Review", where for more than 15 years he was Editor in Chief or member of the Editorial board. For his complete activity Prof. Tadzer has won numerous diplomas, plaques and awards, and among them the following are emphasized: National Award of October 11, Order of Labor of Second Degree, the Award of the City of Skopje - November 13, the Charter of Dr. Trifun Panovski and the Certificate of Acknowledgement awarded by the Macedonian Medical Association for the outstanding results in advancing the medical science, practice and development of the health care and the long-term contribution and promotion of the MMA.