We looked at existing recommendations and supporting evidence on the effectiveness of screening young children for autistic spectrum disorder (ASD) for improving short- and long-term outcomes. We conducted a literature search up to the 8th of November 2019 by using key terms and manual search in selected sources. We summarized the recommendations and the strength of the recommendation when and as reported by the authors. We summarized the main findings of systematic reviews with the certainty of the evidence as reported. There are discrepancies among the recommendations given by different institutions on universal screening for ASD in children. Some recommend that all children should be screened with an ASD-specific instrument during well-child visits at ages 18 and 24 months in conjunction with ongoing developmental surveillance and broadband developmental screening; some conclude that the current evidence is insufficient to assess the balance of benefits and harms of screening for ASD in young children for whom no concerns of ASD have been raised by their parents or a clinician; and others recommend against universal screening, but for a screening among children with high risks. There is adequate evidence that ASD screening tools applied to children between 12 and 36 months accurately identify those with ASD. There is some evidence showing benefit of early interventions applied to children with ASD, from children identified with developmental concern by their family, teacher or clinicians. We found no evidence on the effectiveness of interventions applied to children with ASD detected through screening. Keywords: Screening, Autism spectrum disorder, Preschool child