Professor Simbayi is the Deputy Chief Executive Officer (DCEO) for Research (DCEO-R). He is the founding Executive Director of the HIV/AIDS, STIs and TB (HAST) research programme, the largest and most successful research programme in the HSRC, a position which he held since its founding in July 2010 until 31 May 2016. From July 2007 until June 2009 he also served as the Deputy Executive Director of the then Social Aspects of HIV/AIDS and Health (SAHA) research programme. Between February 2008 and June 2009 he also served as the Acting Executive Director of the SAHA programme, followed by one year as the Executive Director from July 2009 until June 2010. From the time that he joined the HSRC on 1 November 2001 until June 2007, Professor Simbayi served as a Research Director in charge of the Behavioural and Social Aspects of HIV/AIDS Research Unit in SAHA as well as the Regional Coordinator for Southern Africa of the Social Aspects of HIV/AIDS Research Alliance (SAHARA).