Fisherfolks participate in unsafe sexual behaviors which can predispose them to HIV infection. This research was designed to assess the effects of training on HIV/AIDS-related knowledge and sexual behavior among fisherfolks in two fishing communities in Nigeria. Respondents were allocated into Experimental Group (EG, n = 103) and Control Group (CG, n = 105). Data were collected at baseline using a questionnaire which included questions on socio-demographic characteristics, sexual behavior among others. A 3-day HIV/AIDS training was conducted for EG. Fisherfolks in EG and CG with good knowledge were 16.5% and 54.3%, respectively at baseline. The number increased to 100.0% in EG than CG (60%) at follow-up. At baseline, fisherfolks in EG and CG with high riskperception scores were 26.2% and 59.0%, respectively; corresponding figures at post intervention for EG and CG were 100.0% and 70.0% respectively. Training increased HIV/AIDS knowledge, improved risk perception and reduced risky sexual practices among fisherfolks.