To assess the general public's level of knowledge on diabetes mellitus (DM) and identify related sources of information in Cameroon.This was a cross-sectional study conducted in 2015 in two health facilities in Yaoundé and Edéa.We included consenting adults, except health professionals. The level of knowledge on DM was evaluated on 24 points corresponding to 24 questions addressing either DM definition, signs and symptoms, risk factors or complications.Overall, 1524 persons (40.2% males) were included. Almost 99% of respondents had already heard of DM, but only 16.3% had ever received education on DM. The median score for the global knowledge was 79% (IQR 67-88). A person in the close entourage (71.3%) or a health professional (58.8%) constituted the major sources of information; school (13.3%) and media (television (23.6%), newspaper/magazine (10.0%), radio (9.6%) and internet (6.8%) were less common. Younger ages (<45years), lower levels of education, semi-urban residency, were independently associated with a lower level of knowledge on DM.The general public's level of knowledge on DM may be satisfactory, though needing to be improved. Schools and media should be capitalized to educate people on DM, targeting especially young adults and the less educated.