Introduction: Autism spectrum disorders (ASDs) are a group of developmental disabilities characterized by impairments in social interaction and communication, and by restricted, repetitive, and stereotyped patterns of behavior. Symptoms typically are apparent before age three years. Aim: To determine the prevalence of ASD amongst children along ethno-religious lines, where differences might point to potential trigger factors in its causation in a middle to high-income country. Methods: Diagnostic trends of ASD over the past 18 years were examined over a wide geographical area of central Israel, encompassing a database of 331,169 children, aged 3-18 years. Special importance was attached to statistics from different religious and ethno-cultural groups as potentially reflecting discrepancies in diagnosis, reporting, and possible environmentally- related factors in the presentation of a genetically determined syndrome. Results: Overall prevalence was 0.005 (1/200 live births), well below figures from other similar studies abroad and in Israel. Prevalence figures for the ultra-orthodox Jewish community were low (0.0021), when compared with the general population and similar that among Israeli Arabs (0.0017). Time trends indicated a surge in diagnosis of ASD among Israeli Arabs between the years 2008 and 2011, in contrast with a general flattening of figures for the orthodox community. Conclusions: Results indicated that besides discrepancies in diagnosis and reporting factors, there exists a possible relation between the actual expression of ASD, its genetic predisposition and socioeconomic/cultural status as impacting as part of the epigenetic factors in the causality of autism. Our prevalence rates are currently lower than those of ASD in Europe and the USA.