Developmental and Behavioural Paediatrics encompasses all neurodevelopmental and behavioural issues that children and adolescents may encounter across time. The developmental journey of each child starts at birth and screening should be done routinely during all well-child visits at the community medical practitioner level. It involves screening through routine developmental milestones and looking out for deviations as well as identifying red flags in any domain of development, including motor, speech and language, and social development. We screen in order to allow prompt identification and early intervention. The American Academy of Paediatrics recommends developmental screening to be done at 9, 18, and 30 months. Screening tools include the Denver Developmental Screening Test, Singapore as the baseline screening tool and other specific tools such as the Goodenough Draw a Man, the Ages & Stages Questionnaire, the Vanderbilt Rating Scales, and the Modified Checklist for Autism in Toddlers, Revised with Follow-up. Differentiation between Autism Spectrum Disorder and Attention Deficit Hyperactivity Disorder can be challenging at a young age. Differences need to be teased out through a carefully taken history of the early years. The Diagnostic and Statistical Manual – V now allows dual diagnoses, most commonly established in tandem around the age of six. Screening at around the age of five will thus be useful to look for ADHD as an occurring condition amongst those diagnosed with ASD. School readiness should also be looked at around this time. Better awareness and identification will then lead to prompt diagnosis and intervention in order to optimise eventual outcomes.