BACKGROUND & OBJECTIVES It has been hypothesized that abnormal levels of serum nerve growth factor (NGF) may represent a serological marker for autistic children who may develop cognitive impairment, regression and finally epilepsy. The objective of this preliminary study was to measure serum NGF concentrations of autistic children and compare these levels with those of healthy children. METHODS Consecutive children who were referred to the Paediatric Neurology and Child Psychiatry Policlinics of Dr. Behçet Uz Child Disease and Pediatric Surgery Training and Research Hospital, Turkey between February and September 2008 were included in the study. Serum samples were analyzed for NGF levels using ChemiKine NGF Sandwich ELISA Kit. Comparisons between the study and the control groups were made using student's t test and Chi-square test. RESULTS Forty-nine autistic children and an equal number of healthy children (control group) were included in the study. No significant difference was found between the study and the control groups in terms of children's age, while number of boys was significantly higher (P<0.05) in the study group. Average serum NGF concentrations were 46.94 ± 51.40 and 32.94 ± 12.48 pg/ml in the study and control group, respectively. Serum NGF concentrations were significantly higher (P<0.05) in the study group compared with the control group. INTERPRETATION & CONCLUSIONS Our preliminary findings show that enhanced serum NGF concentration may be used as a potential diagnostic tool in autism, however, further studies including a large number of patients are required to confirm the findings.