Autism spectrum disorder (ASD) is ranked among neurodevelopmental and neuropsychiatric disorders with clinical onset in childhood. In recent years, this disorder has come to the forefront of scientific interest, mainly due to increasing prevalence of up to 1/68 in 2014. The genetic causes of the disorder and the pathophysiological mechanisms that might be involved in the development of ASD are revealed. Comorbid occurrence with epilepsy is quite common, in up to 46% of cases. This article summarizes the cur rent knowledge in this field with a focus on the hypothesis of excitatory-inhibitory imbalance. Some genetic causes of ASD and cur rent diagnostic options are also discus sed. The pathophysiology of the co-morbidity of ASD and epilepsy is discus sed in terms of possible therapeutic interventions.