Objective: The aim of the study was to determine the prevalence and awareness of particular types of oral parafunctions in young healthy students and any association with temporomandibular disorders (TMD). Material and methods: The study was performed in a randomly selected group of 303 healthy students (mean age 18.8 years) from the vocational technical school in Wrocław, Poland, who underwent a routine clinical examination and functional analysis of the mouth. On taking the history all subjects were asked about their awareness of various forms of parafunctional activity in their mouth. Results: Almost all subjects revealed various oral parafunctions such as: bruxism, nail and pen biting, chewing gum, and biting the mucosa of lip or cheek. These habits were present singly or as double, triple or even fourfold coincidences in a single person. The most frequent oral parafunctions were habitual gum chewing and bruxism. Subjects were very seldom aware of the last parafunction. TMDs were more prevalent in the presence of bruxism than in other oral parafunctions. Conclusions: The studied students revealed various types of oral parafunctions, however most of them were not aware of clenching and grinding their teeth. Key words: bruxism, chewing gum, dental attrition, tooth wear, temporomandibular disorders, TMD, oral parafunctions