Polysomnography is considered the ‘gold standard’ in the diagnosis of sleep apnoea but it is expensive and difficult to perform in children. Diagnosis based on subjective judgement is often inaccurate. An accurate diagnostic scale based on clinical parameters could obviate the need for polysomnography and help establish or exclude the presence of OSAHS. In this study, graded clinical variables such as history of snoring or gasping, nasal obstruction, rhinorrhoea, palatine tonsil size, adenoid to nasopharynx ratio by lateral cephalometry and tympanogram were assessed in the ‘study group’ and compared with the polysomnography results in the ‘validation group’. The clinical parameters were considered as independent variables and the polysomnography result as a dependent variable if it met the OSAHS criteria. Logistic regression analysis was applied and this revealed significant correlation between polysomnography data and history of snoring and gasping (×1), palatine tonsil size (×2) and adenoid to nasopharynx ratio (×3) when using the finally derived equation, from which a value of more than 13 predicted OSAHS. The diagnostic scale does not give the severity of OSAHS but provides an effective screening tool which is important in the early diagnosis of this condition. Twenty percent of children snore and there is often pressure by parents for intervention. Considering that only one to four percent have OSAHS, treatment options might be based on this formula once it is more established with the help of wider studies.