2Background: Preventive chemotherapy (PCT) is the main strategy currently used to 3 control and/or eliminate onchocerciasis (Oncho), lymphatic filariasis (LF) and Soil 4 Transmitted Helminthiasis (STH), and community participation (through 5 implementation of MDA or adherence to PCT) is critical to achieve this goal. However, 6 these Neglected Tropical Diseases (NTDs) are still persisting in most endemic areas as a 7 consequence of sub-optimal treatment coverage, the presence of systematic non-8 compliers in communities ... This study aimed at investigating whether the knowledge, 9 attitudes and practices of populations about these NTDs can explain the poor trends 10 towards elimination. 11 12 Methodology: A cross-sectional survey was carried out in the Mbengwi Health District 13 (North West Region, Cameroon) using the cluster sampling technique. Clusters were 14 selected using the Probability Proportionate to Estimate Size strategy. In each cluster, 15 the random walk technique was used for the selection of households, and a structure 16 questionnaire was administered to 2-3 of its members. 17 18 Principal Findings: A total of 254 households from 26 clusters were visited, and 514 19 individuals were interviewed. The sex ratio of interviewees (1.08) was unbiased, and 20 their ages ranged between 10 and 99 years old. Though most of the respondents 21 declared having already heard of these NTDs (41.2%, 73.7% and 89.9% for Oncho, LF 22 and STH respectively), only a minority of them were aware of correct response of how 23 they are acquired/transmitted (3.7%, 6.8% and 12.5% for Oncho, LF and STH 24 respectively), and prevented (23.1%, 18.9% and 47.2% for Oncho, LF and STH 25respectively). Even when respondents were aware that medicines were useful to 3 1 prevent and/or treat these NTDs, almost none of them knew the drug used or the 2 treatment frequency. 3 4 Conclusion/Significance: This study reveals that interviewees exhibit poor knowledge, 5 attitudes and practices as regards to these NTDs, although they are endemic in the study 6 area and PCTs given yearly since a while. These misconceptions can seriously affect the 7 adherence and contribution of populations to the success of PCTs, and it appears 8 compulsory to improve individual knowledge, with a focus on the importance and 9 rationale behind MDA, to optimize their attitudes and practices, especially community 10 participation to PCTs. Mbengwi health district, Cameroon 14 15 16 Author summary 17 The control and/or elimination of Neglected Tropical Diseases (NTDs) are currently on 18 top of the agenda of endemic countries' control programs and stakeholders. Ivermectin-19 and Albendazole/Mebendazole-based mass distribution is currently the main strategy to 20 control/interrupt transmission of onchocerciasis, lymphatic filariasis and soil-21 transmitted helminthiasis, and adherence of communities is compulsory for the success 22 of this approach. Despite the success registered in the fight against these diseases, the 23 trend towards elimination remains unsatisfa...