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Background Allergic rhinitis (AR) is a common disorder, which causes a considerable burden both on individual patients and society, particularly in large cities where air pollution is the substantial problem causing respiratory diseases. AR constitutes a worldwide public health problem. However, little is known about allergic diseases in Africa because of a lack of data and resources and by the difficulty, or even absence of diagnostic tools in sub-Saharan Africa. Objective The present PhD project aimed to study epidemiology and clinical characteristics of AR and associated diseases in both urban and rural areas of Kinshasa, and to assess the risk factors and allergen sources in order to improve the disease management. Methods The present work was done by combining studies in the general population, among patients presenting with nasal symptoms and among individuals exposed to flour dust in comparison to the controls. The first cross-sectional clustered survey was done from February to May 2010 on inhabitants of 8 health zones randomly selected in Kinshasa. A total of 1412 individuals (aged from 5-83 year-old) were interviewed and 1005 of them skin tested. The second cross-sectional study enrolled 423 consecutive outpatients presenting (January- May 2009) with nasal symptoms related to rhinitis/rhinosinusitis at the ENT services of Kinshasa. Patients were face-to-face interviewed and skin tested. The last study was conducted from April to August 2012 among 809 consecutive individuals: 263 workers directly exposed to flour dust, 278 indirectly exposed to wheat flour and 268 controls. Individuals were questioned and skin prick tests (SPT), nasal and pulmonary parameters were assessed. Results In the general population, 62% of respondents reported at least one disease in the 12 previous months. The 12-monthprevalence of rhinitis, rhinoconjunctivitis, wheezing and skin itch-rash symptoms was of 30.8%, 24.4%, 15.4% and 6.2% respectively. Rhinoconjunctivitis and wheezing were significantly more prevalent in urban individuals, while skin itch-rash was significantly more prevalent in rural individuals. Although not statistically significant, rhinitis seemed more prevalent in urban than in rural areas. Twenty three percent of individuals showed positive SPT results with dermatophagoides pteronyssinus (DPT) and cockroach being the most prevalent allergens. AR and non-allergic rhinitis prevalence was of 13.9% and 27.9% respectively. 59.7% and 48.0% of AR individuals expressed moderate to severe and persistent symptoms respectively. In multivariate analysis having any diseases were associated with active smoking, presence of cockroach in the home, history of atopy among siblings, personal history of atopy, using a straw or herbs mattress and positive SPT responses. The study of rhinologic patients highlighted that about one third of patients had positive SPT results, with 40.9% of these showing polysensitization. DPT and cockroach were the most common allergens among sensitized patients. Persistent and moderate/severe AR represented 61.4% and 69.3% respectively. Sensitization was indenpendently associated with younger age, rhinoconjunctivitis in the past and reaction to non-specific triggers factors. The results of individuals exposed to flour dust revealed that, the 12-months prevalence of rhinitis, rhinoconjunctivitis, wheezing and nocturnal cough was of 46.0%, 15.8%, 10.6% and 7.5% respectivelyamong all respondents. Compared to the controls, rhinitis, rhinoconjunctivitis and nocturnal cough were significantly more prevalent in workers directly exposed to flour dust. 37.5% of all respondents showed positive SPT results with DPT and cockroaches being the most prevalent allergens. Sensitization to storage mite was found more prevalent among workers directly exposed than controls, while positive SPT to pollen mix, sunflower pollen and crab were more prevalent inthe control group. In multivariate analysis, belonging to the directly exposed group and the presence of a flour mill in the neighborhood significantly increased the risk of having airway disease. Mice in the house increased the risk of both sensitization and airway diseases. Conclusion The present work revealed a high prevalence of allergic diseases in Kinshasa, especially in urban areas compared to rural parts. A substantial portion of the population and patients showed sensitization to at least one allergen. DPT and cockroaches constituted the most prevalent allergen sources. Allergic diseases were associated with many factors. It is important to increase awareness toward allergic disorders and to ensure adequate management and prevention. Keywords: prevalence, rhinitis, rhinoconjunctivitis, wheezing, itch-rash, sensitization, flour dust, Kinshasa