Нe was born in 1934 in Tashkent - Head of Pulmonology and Clinical  Allergology Department of Tashkent Institute for Professional Development of Doctors, Leading Researcher - Pulmonologist and Phthisiologist of Uzbekistan, well known in the countries of Central Asia, Russia and far aboard. 
In 1958 he graduated from Tashkent State Medical Institute. After graduating from institute he has been working in Tashkent Institute for Professional Development of Doctors for 50 years where he also had training in the clinical residence and candidate's training programme. He had his doctor's training programme in A.L. Myasnikov Cardiology Institute (Moscow). Since 1978 he has been Head of Clinical Pulmonology Department, and he initiated the organisation of this department in Tashkent Institute for Professional Development of Doctors. 
Being Head of Department and Teacher he was involved into administrative work, for 12 years he had been the Dean of General Medicine Department and Pro-rector for Clinical Work.  
In 1964 he defended his candidate's thesis, and in 1974 - doctor's thesis. In 1979 he was awarded with Professor's title, in 1995 he was selected to be correspondent member of Uzbekistan Academy of Sciences, in 2000 - Academician of Uzbekistan Academy of Sciences, in 2005 - Honored Doctor of the Russian Academy of Medical Sciences. 
Being a leading specialist in pulmonary diseases in 1986 he was appointed to the position of Director of Uzbekistan Tuberculosis Research Institute, and under his command the institute developed its research and practical activities, got actively involved into research in pulmonology, became the center coordinating research and practical activities on this issue and later the institute was renamed into Phthisiology and Pulmonology Research Institute by the Uzbekistan Ministry of Health.
Prof. Ubaydullaev is the author of more than 600 publications, including 12 monographs, 10 inventions and more than 40 guidelines. 
He is Editor-in-Chief of scientific journal Annals of Central Asia Pulmonologists' Association, which has been published since 1996.
Prof. Ubaydullaev was the first to initiate research in pulmonary diseases in Uzbekistan, he founded the academic school of pulmonologists. He was an academic advisor for 35 candidate's and 22 doctor's theses. Scientific achievements of Prof. Ubaydullaev and his followers are acknowledged aboard. Every year he presents the achievements of Uzbekistan in pulmonology and phthisiology at the international conferences.
He initiated and organized joint symposia with French and German scientists in Tashkent (1986) and Samarkand (1991). He was the first in Uzbekistan to receive the international certificate on functional research of the respiratory system (Germany, Gohberg).
Under guidance of Prof. Ubaydullaev a number of programme documents on tuberculosis and pulmonology has been developed - Law of the Uzbekistan Republic On Protection of Population from Tuberculosis, State Programme on Prevention of Tuberculosis and Reduction of Tuberculosis Incidence in Uzbekistan, Programme on Tuberculosis Detection and Treatment on Pilot Territories, Edicts by the Uzbekistan Ministry of Health on Tuberculosis Care Improvement, Regional Programme of Central Asia Pulmonologists Association on Prevention and Reduction of Prevalence of Respiratory Diseases in the Region for 1997-2000, Agreement on Asthma: Strategy of Diagnostics, Prevention and Treatment in Central Asia, Formulary System on Tuberculosis (2000) etc.
He is actively involved into community work. Prof. Ubaydullaev actively cooperates with WHO and other international and foreign organisations.
He is a member of European Respiratory Society (since 1990), International Union Against Tuberculosis and Lung Diseases (1996), President of Central Asia Pulmonologists Association (1994-2000, since 2008), Chair of Scientific Medical Society of Phthisiologists and Pulmonologists of Uzbekistan (since 1987), Elect-President of Euro-Asian Respiratory Society (since 2006). 
In 2004 Prof. Ubaydullaev was awarded as the Best Doctor of the Year as the best specialists of Uzbekistan. In 2007 he was awarded with the Order of Merit (Buyuk xizmatlari uchun).