There is a substantial gap between what we "need to know" and what we "actually know" to practise evidence-based paediatrics. Good evidence from primary research studies about effective child healthcare strategies (for individuals or populations) for a broad range of important issues is lacking. Systematic reviews of existing good-quality research evidence, or evidence-based clinical practice guidelines relevant to child health, are often not readily available or accessible to practising clinicians. Recent initiatives to supply the information needs of paediatricians should lead to improvements in the availability, accessibility and applicability of the "evidence-base". These efforts need wider commitment and further resources. The gap between what we already "know" and what we "actually do" in daily practice is even wider. We need to improve our efforts to implement existing research knowledge, using strategies with demonstrated effectiveness, to promote the timely transfer of research evidence into actual practice. The health outcomes of these efforts need to be systematically evaluated.