The reign of apartheid in South Africa was characterized by systematic violation of the human rights of the Black population. Ruling institutions of the country perpetuated and enforced such violations. Consequently, Black South Africans may be apprehensive of scientific research in which the Black population is targeted for participants, regardless of the reason for their being selected. This exploratory study aims to (1) contribute to the relatively limited body of empirical research on the concept of voluntariness and (2) assess racial differences in public perceptions of the voluntariness of medical research participants. We sampled 111 employees from two companies. The sample consisted of 39 Black, 37 Indian, and 38 White participants. A structured questionnaire was used to interview respondents. Results showed that Black respondents scored significantly lower on scores of perceived voluntariness than both Indian and White respondents. These racial differences in perceptions of voluntariness were found to be independent of level of education, knowledge of medical research procedures, and close or personal experience of medical research. Perceptions of voluntariness did not however appear to impact on participants' personal willingness to participate in future research. Implications for recruitment of future health research participants in South Africa are discussed.