Open Defecation (OD) which is exposing or disposing human feaces in the open environment like bushes, forests, fields, streets, ditches, etc, without cover has been an ancient practice with little or no known harm to human health then. But today, according to recent UNICEF report, open defecation is the worst kind of sanitation challenge globally and Nigeria which used to be number three in open defecation practice in the world after India and China is now topping the list. This study is premised against the background that there is an increasing global attention to the threats of open defecation to human health, dignity and the environment and open defecation facilitates the transmission of infectious diseases like diarrhea, typhoid, cholera and other diseases associated with poor sanitation, hygiene and waste management. To help address the health concerns and ameliorate the spread of these diseases in Nigeria, the Federal Government and other International Development Partners like UNICEF began the Open- Defecation - Free (ODF) campaign messages in the country. ODF messages aimed at providing adequate information and awareness on the negative effects of open defecation practice and to sensitise the people to adopt behavioral change of saying no to open defecation practice but rather use the toilet to achieve an ODF environment. In all these, it is not clear if the residents of Anambra State, one of the pilot States in ODF messages and campaign in Nigeria representing the South East Zone are favorably disposed to these awareness and behavioural change messages and interventions. This circumstance therefore motivated the study titled “Open-Defecation-Free Messages: A knowledge, Attitude and Practice (KAP) Study of Residents of Anambra State” which set the following objectives; to determine whether respondents in Anambra State have knowledge of ODF messages, to ascertain the respondents’ sources of information about ODF messages, to ascertain the respondents’ sources of information about ODF messages, to determine whether there is a significant relationship between knowledge of ODF messages and the respondents’ attitude towards these messages, to find out whether there is a significant relationship between respondents’ attitudes to ODF messages and the practice of these messages, and to determine whether respondents in Anambra State advocate for ODF practice after exposure to ODF messages. Three null hypotheses were subjected to empirical test in the study. The study was anchored on Diffusion of Innovation theory and Theory of Reasoned Action. It adopted a Survey research method with questionnaire as instrument of data collection. A sample size of 400 was drawn from the study population of 1,170,100 using the Taro Yamane’s formula. Purposive Sampling technique was used to draw samples of both genders from community members across the four UNICEF intervention Local Government Areas of Anambra State which are Aguata, Anambra East, Nnewi North and Idemili South LGA’s. Simple percentages, frequency tables, mean scores and Chi-square were used for the analysis. Findings from the study reveal that respondents from the area of study have knowledge of ODF messages and that their main source of information are radio, flyers/posters, and interpersonal channels. However, findings show that respondents do not have a positive attitude towards practice of ODF messages even after exposure to ODF messages as majority still indulge in open defecation practices. Based on the outcome of the study, the work recommended the following; more sensitization workshops on the need to adhere to ODF practices, follow up efforts by Open-Defecation-Free campaign officials to ensure compliance, friendly monitoring teams comprising community members, use of radio, flyers, posters and interpersonal channels for ODF communication campaign, economic assistance to communities for latrine construction and provision of public toilets in the intervention communities. Based on the outcome of the study, the researcher developed Inclusive Action Cycle (IAC) model as a contribution to knowledge. The major premise of this model posits that health communication messages should begin and end with members of the target communities from the planning to execution and monitoring stage. Examples of open-defecation-free messages include thus:, Stop OD – Use the toilet, This is ODF Community: Do not defecate in the open – Fine N5000, Keep your environment safe: Build a latrine.