Prof. Mati was born in Migwani Location, Kitui County in 1938. He attended Alliance High School before proceeding to Makerere University College where he was awarded M.B. and Ch.B. degrees in medicine and surgery in 1965. After his postgraduate professional training in Glasgow and London, he joined the Department of Obstetrics and Gynecology of the University of Nairobi in 1970. He served as a full Professor and Chairman of the Department of Obstetrics and Gynecology at the University of Nairobi. To date over 50 specialists in obstetrics and gynecology have trained under his tutelage. He was a member of the Kenya Obstetrical and Gynecological Society, editor of the Journal of Obstetrics and Gynecology of Eastern and Central Africa and Editor-in-Chief of the Kenya Journal of Sciences. He served on various national and international professional committees. His main research interest is in aspects of Reproduction; and in 1978 he played a major role in the establishment of the National Centre for Research in Reproduction (NCRR) of which he served Chairman since its inception. He has published over 70 papers.