The onset of Attention Deficit / Hyperactivity Disorder (AD/HD) usually occurs during the preschool years but the diagnosis of the disorder is rarely made before the child enters the primary school (APA, 1994). Even in the DSM-IV, the validity of the diagnosis for this age is not adequately established, as the presentation of preschool children in the DSM-IV field trials was relatively low. However, early diagnosis and intervention may increase the likelihood of successful outcomes. Thus, it is crucial to investigate how parents, who are the main referring agents, perceive the nature and severity of AD/HD symptoms at preschool years. Parents (both fathers and mothers) of 295 preschoolers, aged 4-6, enrolled in kindergartens in Athens completed: a) the Strengths and Difficulties Questionnaire (SDQ; Goodman, 1997) regarding their own child, for the screening of AD/HD and b) a questionnaire composed by a vignette displaying a five-year old child presenting AD/HD symptoms, and three rating scales assessing perceptions of the nature and the impact of these symptoms. Results showed that parents whose child presents AD/HD at preschool age perceive AD/HD symptoms as less severe, untypical and with less negative impact on the child?s life than parents whose child doesn?t display such behaviours. To conclude, the primary symptoms of AD/HD at preschool years are often perceived by parents as normal developmental characteristics of the child?s behaviour at this age. Such false beliefs may delay the early diagnosis of the disorder, which would lead to the implementation of an intervention program and to the prevention of secondary difficulties, like learning and behaviour problems that often develop when these children enter primary school. The potential contribution of the nursery teachers to the early identification of AD/HD and to the referral of the child is discussed.