Current evidence shows that early interventions in children with autism spectrum disorder (ASD) are more efficient and associated with better long-term outcomes. This also highlights the need for early recognition of children with ASD symptoms by family physicians and referral to child psychiatrists. This study aimed to evaluate how family physicians' knowledge about ASD is reflected in clinical practice by making a diagnostic evaluation of the cases referred with suspected ASD. The study included 149 cases that family physicians referred to child psychiatrists regarding the assessment for ASD. Diagnostic evaluation of the subjects was carried out using the Diagnostic and Statistical Manual of Mental Disorders, fifth edition (DSM-5) criteria. Childhood Autism Rating Scale (CARS) and Autism Behavior Checklist (ABC) were used in the evaluation process. Denver II developmental screening inventory was used to evaluate all subjects under six. The mean age of all participants was 39.1 (±13.2) months, and in ASD cases, it was 34.6 (±7.8) months. Of all referred cases, 72,5% were diagnosed according to the DSM-5 criteria. The most common diagnoses were global developmental delay (28.9%), language disorder (15.4%), ASD (15.4%), and attention deficit hyperactivity disorder (8.7%), respectively. The most common reason for referral specified on the consultation note was delayed speech, with a rate of 87.2%. In addition, 148 (99.3%) of the symptoms noted on the referral note were clustered within the DSM-5 ASD A criteria and 19 (12.8%) within the ASD B criteria. Developmental delay was more prominent in cases with ASD when compared to those with global developmental delay and language disorder. The most common diagnosis was a global developmental delay in referred cases, and only some of the symptoms seen in ASD from the referral notes of family physicians stood out as the reason for referral. These results underline the necessity of continuing ASD training for family physicians.