Abstract This study examined the effectiveness of HIV/AIDS communication approaches employed by intervention agencies in Abia and Imo States, Nigeria, with a focus on how these approaches influence key outcome variables such as awareness, attitudes, and preventive behaviours among residents. The study was anchored on Diffusion of Innovations Theory, Social Cognitive Theory, and Framing Theory, which provided a framework for understanding how communication strategies shape knowledge, perceptions, and behavioural responses. Using a descriptive survey design, structured questionnaires were administered to 400 residents, out of which 378 were properly completed and analysed, alongside semi structured interviews with 22 key stakeholders. The independent variable in the study was HIV/AIDS communication approaches, while the dependent variables included level of awareness, attitudes toward HIV/AIDS, and preventive behaviours. Findings revealed that intervention agencies utilize a combination of community outreach, peer education, radio and television campaigns, social media platforms, and interpersonal communication strategies. About 68 percent of respondents reported regular exposure to HIV/AIDS messages, indicating a wide reach of communication efforts. The level of awareness was generally high, with 72 percent of respondents demonstrating moderate to high knowledge, although gaps were observed among rural populations. In terms of attitudes and behaviours, 65 percent of respondents reported adopting safer practices such as consistent condom use and regular HIV testing, with a mean score of 3.0 and standard deviation below 1.0, suggesting relatively consistent responses. The study also identified major challenges including limited funding, inadequate personnel, and socio cultural barriers, reported by 59 percent of respondents. Comparative analysis showed slight differences between the two states, with Imo State recording higher engagement levels than Abia State. Thus, the findings imply that HIV/AIDS communication approaches significantly influence awareness, attitudes, and preventive behaviours. Based on this understanding, the study recommends strengthening integrated communication strategies, improving resource allocation, and tailoring interventions to local socio cultural contexts to enhance effectiveness.