Significant progress has been made over the past two decades in the development of early screening instruments for autism spectrum disorder (ASD). Whilst it is possible prospectively to identify cases of ASD using screening instruments, few of the many available screening instruments have been well validated. The American Academy of Pediatrics, which advocates universal screening, and the UK National Institute for Health and Care Excellence (NICE), which does not, make very different recommendations. It is critical that those using screening instruments in clinical practice understand how to interpret data from published studies, in particular recognising the low positive predictive value of a single administration. Clinicians should receive training in how screening information is communicated to parents. As part of ongoing surveillance, completion of early autism screening instruments can provide valuable information on potential early emerging symptoms of ASD and other neurodevelopmental disorders.