We aimed to estimate the population prevalence of obstructive sleep apnoea (OSA) in an urban community of German third graders (age range 7.3-12.4 yrs) and the diagnostic test accuracy of two OSA screening methods. Using a cross-sectional study design with a multi-stage sampling strategy, 27 out of 59 primary schools within the city limits of Hanover, Germany, were selected. 1,144 third graders were screened for symptoms and signs of OSA using questionnaires and nocturnal home pulse oximetry. 183 children underwent abbreviated nocturnal home polysomnography (OSA definition: apnoea/hypopnoea index ≥1) and 22 were diagnosed to suffer from OSA. In general, sensitivity for both screening methods was low (<0.6), while specificity was moderately high (mostly >0.7). Independent predictors for OSA were body mass index, history of allergy, a composite questionnaire score, and two oximetry-based criteria. Based on these variables and logistic regression, a prediction model (accuracy; 95% confidence interval: 0.86; 0.71-0.94) was constructed and applied to children who had not successfully undergone polysomnography. This resulted in nine additional OSA cases and an overall design-adjusted population prevalence (95% confidence interval) of 2.8% (1.5-4.1%). Clinical and oximetry findings may be helpful for screening and predicting OSA in primary school children.