People living with undiagnosed HIV are big contributors to the transmission of the virus. Although measures have been made to scale up HIV prevention and voluntary counselling and testing in sub-Saharan Africa, testing coverage remains low in many sub-Saharan African countries, including Mozambique and Kenya, where most people live with HIV/AIDS. Studies have shown that, in most countries in sub-Saharan Africa, men are less likely to test for HIV compared with women. This study examined the relationship between comprehensive HIV/AIDS knowledge and HIV testing among men in Kenya and Mozambique. Data were from the men's re-code file of the Demographic and Health Surveys of Mozambique and Kenya. Binary logistic regression models were generated and the results presented as crude odds ratios (cOR) and adjusted odds ratios (aOR). The prevalences of HIV testing in Kenya and Mozambique were 80.1% and 46.7%, respectively. Men in Mozambique who had comprehensive HIV/AIDS knowledge (aOR=1.26, CI: 1.07-1.47) were more likely to test for HIV compared with their counterparts who had no comprehensive HIV/AIDS knowledge. In Kenya, men who had comprehensive HIV/AIDS knowledge (aOR=1.23, CI: 1.09-1.39) were more likely to test for HIV compared with their counterparts who had no comprehensive HIV/AIDS knowledge. This study found a statistically strong significant association between comprehensive HIV/AIDS knowledge and HIV testing among men in Kenya and Mozambique. To improve HIV testing rate among men, it is important that interventions are geared towards improving men's comprehensive HIV/AIDS knowledge, perhaps by expanding HIV/AIDS education programmes and campaigns. This could improve HIV testing rates and ensure the realization of the global HIV/AIDS target of 95-95-95 by the year 2030.