Childhood functional constipation has an estimated prevalence of 3% in the Western world and is probably the most common gastrointestinal complaint in children. It is characterized by infrequent painful defecation, faecal incontinence and abdominal pain. Only less than 5% of children with constipation have an underlying disease. Only recently two evidence-based guidelines (the Netherlands and Great Britain) have been developed concerning the diagnostic and therapeutic approach for childhood constipation which we both discuss in this article. At present, a thorough medical history and complete physical exam are usually sufficient to confirm the diagnosis of functional constipation. Further laboratory or radiological investigations should only be performed in case of doubt, to exclude an underlying disease. Treatment of childhood constipation consists of four steps: (1) education, (2) disimpaction, (3) prevention of re-accumulation of faeces and (4) follow-up. Surprisingly, there is only limited evidence that laxative treatment is better than placebo in children with constipation. However, according to the available evidence, the Dutch guideline recommends lactulose for children <1 year as first-choice treatment. For children below the age of older than 1 year, both lactulose and polyethylene glycol (PEG) with or without electrolytes can be used as first-choice treatment. According to the National Institute for Health and Clinical Excellence guideline, PEG plus electrolytes is the first-choice treatment for all ages. Conclusion: Children with functional constipation should be diagnosed and treated according to recently developed evidence-based guidelines. © 2011 Springer-Verlag.