The aim of this study was to describe the prevalence of signs and symptoms of temporomandibular disorders (TMD) in a group of patients seeking orthodontic treatment. One hundred and ninety one consecutive prospective orthodontic female patients, divided into three age groups of 8, 14 and 18 years, were examined for TMD signs and symptoms and orthodontic treatment need (IOTN). The percentages of signs and symptoms found were 41 and 30%, respectively. No significant association was found between IOTN and TMD signs and symptoms. The youngest age group reported significantly less headache and temporomandibular joint (TMJ) noise. Headache was significantly associated with all TMD symptoms and with tenderness to palpation. In conclusion, the results indicate that malocclusion could not be considered as a primary aetiologic factor for TMD within the age range studied.