Objective: This study has planned to investigate the role of electroencephalography (EEG) and cranial magnetic resonance imaging (cMRI) in the evaluation and diagnosis of neurological disorders combined with autism in children. Method: A total number of 121 autistic children ranging from 3 to 18 years of age and who had applied to our hospital's clinics between January 2010 and January 2011 were included. The sociodemographic properties, time of birth, birth history, weight at birth, age at onset of walking and language development were investigated. By means of a reevaluation of cMRI, sleep EEG and other examination findings, additional neurological diagnoses, if any were recorded. Children for whom, a cMRI/EEG evaluation was carried out and for whom such an evaluation was not carried out was compared statistically as to certain risk factors separately for additional diagnoses and neurological disorders. In addition, the relationship between cMRI and EEG findings and additional neurological disorder was examined. Results: Autistic children (Male/Female: 92/76) aged 9.30±4.2 years have been diagnosed neurological disorder additionally with a percentage of 40%. The most common of these was the epileptic seizure as 33%. No data was obtained about an additional neurological disorder in 22% of cases who performed cMRI and in 34% of cases who performed EEG. Ratio of presence of a pathological finding in cMRI was high in patients with cerebral palsy, whereas it was not found to be meaningful in patients with epileptic seizures. Analyzing risk factors for neurological disease, birth history of perinatal problems and gait disorders were seen more frequently in patients who required cMRI as compared to those in patients who did not require cMRI. Gait age was older in patients who required cMRI (18±8 months) as compared to patients without cMRI (14±4 months). Conclusion: In our autistic children, cMRI and EEG examinations had been extensively used for the investigation of additional neurological disorders. Both cMRI and EEG examinations had been requested more frequent in the presence of perinatal problems. The other risk factors for additional neurological disorders were history of premature birth to request EEG and older age at onset of walking, walking problems to request cMRI. However with detailed clinic evaluation of autistic children and clarification for investigations criteria unnecessary EEG and cMRI should be avoided.