The purpose of this study was to evaluate associations between periodontal diseases and the common risk factors in Ilala, Tanzania. To determine behavioural and socioeconomic background, a total of 1764 subjects (827 males and 937 females) aged 3-84 years were randomly selected and interviewed. The subjects were examined clinically for the presence of plaque, calculus, gingival inflammation, periodontal probing depths and gingival recessions. Logistic regression analyses showed that the risk factors for gingivitis were male sex, presence of plaque or calculus and use of local "mswaki", the risk factors for periodontal pockets were age of 35 years or more, presence of plaque, and rural residence. The risk factors for gingival recession were identified as age of 35 years or more, male sex, lower educational status, presence of plaque and gingival inflammation. The most significant risk factors to have periodontal diseases in this study population were age, sex, education, rural residence, plaque and calculus.