Objectives: Autism spectrum disorder (ASD) is a common neurodevelopmental disorder in childhood, affecting one in 68 children. Many children with ASD exhibit recognizable problems in social interactions in their first year of life. Although some mothers recognize problems earlier, the diagnosis of children is delayed due to various reasons. In this study, it is aimed to investigate the association between parental autistic traits, alexithymia and child’s problematic behaviours and diagnostic delay. Materials and Methods: A total of 80 children with ASD and their parents have been included in the study. Autism quotient (AQ), Toronto Alexithymia Scale and Aberrant Behavior Checklist were given to mothers. The socio-economic status is measured with Hollingshead-Redich Scale. Results: It is found that the average age of ASD diagnosis was 35.73±12.03 months and the average age that parents first noticed symptoms was 27.07±9.43 months. It is also detected that there was an average of 9.66±8.89 months delay between mothers noticing the symptoms in their children and bringing them to the child and adolescent psychiatry clinic. This difference has shown a significant positive correlation with the scores of the AQ-social skills subscale of the parents. Conclusion: This study is important both in terms of presenting data related to the age of the diagnosis of ASD in Turkey and in terms of providing information about the diagnostic delay. Multi-centred studies with larger samples which also include data about follow-ups are required on this subject.