Background: Stigma and discrimination against people living with and affected by HIV/AIDS undermines the effectiveness of national efforts to prevent and control the HIV epidemic. In the context of Tanzania, evidence on the incidence of HIV/AIDS-related stigma and discrimination from the perspective of the employees and employers is limited. Objective: To provide an assessment of the pervasiveness of HIV/AIDS-related stigma and discrimination in the workplace in Tanzania. Methods: A cross-sectional study, which employed both qualitative and quantitative techniques, was carried out. Some 181 employees from 23 workplaces participated in the study. Results: About 13% of the respondents reported existence of some forms of discrimination while about 16% of the respondents divulged existence of complaints on stigma for HIV/AIDS affected/infected employees in their workplaces. Stigma-related complaints varied between cities, public or private, nature of activity of workplace, and whether the employee had a member of the family who was living with HIV/AIDS (p<0.1). Conclusion: Effective strategies to end HIV/AIDS-related stigma and discrimination in the workplace should consider the context in which the strategies are to be implemented. HIV/AIDS-related education and availability of health and social supports to HIV/AIDS affected/infected employees could help lower self-stigma and discrimination among affected/infected employees in the workplaces.