HIV/AIDS is a major pubic health problem in Nigeria. This paper identifies the ethical issues involved in HIV/AIDS biomedical and behavioural research, counselling and testing in the country. These concerns are discussed in the context of the three universal ethical principles of respect for persons, beneficence, and justice. Written informed consent, which is a component of respect for persons, is a challenge in Nigeria because of skepticism to documentation, sensitivity of sexual practices often explored in behavioural research, and a tradition that discourages patients from questioning medical authority. Although monetary inducement of research participants is ethically acceptable, the high levels of poverty in Nigeria raise concerns that payment of money may unduly induce indigent participants to enroll in research. The disclosure of results in situations when married HIV positive persons insist that their status should not be revealed to their spouse illustrate the dilemma that health workers face in adhering to the ethical norm of keeping confidentiality and the public health obligation of preventing HIV transmission in a third party. Some recommendations are offered to address these concerns.