INTRODUCTION: The epidemic of HIV in sub-Saharan Africa varies significantly across countries in the region with high prevalence in Southern Africa and Nigeria. Cancer is increasingly identified as a complication of HIV infection with higher incidence and mortality in this group than in the general population. Without cancer prevention strategies, improved cancer treatment alone would be an insufficient response to this increasing burden among people living with HIV (PLHIV). Although previous studies have noted low levels of awareness of cancers in sub-Saharan Africa none has examined the knowledge and perceptions of cancer among people living with HIV/AIDS. METHODS: Focus group discussions (FGD) and Key Informant Interviews (KII) were carried out in 4 high volume tertiary care institutions that offer HIV care and treatment in Nigeria. FGD and KII assessed participants' knowledge of cancer, attitudes towards cancer risk and cancer screening practices. RESULTS: The mean age (SD) of the FGD participants was 38 (2.8) years. Most participants had heard about cancer and considered it a fatal disease but displayed poor knowledge of the causes of cancer in general and of AIDs associated cancers in particular. PLHIV in Nigeria expressed fear, denial and disbelief about their perceived cancer risk. Some of the participants had heard about cancer screening but very few participants had ever been screened. CONCLUSION: Our findings of poor knowledge of cancer among PLHIV in Nigeria indicate the need for health care providers and the government to intervene by developing primary cancer prevention strategies for this population.