Twin to twin transfusion syndrome (TTTS) affects 10 to 15% of monochorionic twin pregnancies. Untreated, perinatal loss exceeds 80%, of which survivors have a great risk for long-term neurological disorders as psychomotor retardation or cerebral palsy. TTTS can be treated using foetoscopy and selective ablation of the twin-to-twin blood vessels under local or regional anaesthesia. However, local or regional anaesthesia does not always result in excellent maternal comfort, nor does it provide foetal immobilisation, necessary for optimal surgical conditions. Using a continuous infusion rate of remifentanil 0.1 microg/kg/min, perfect foetal immobilisation and excellent maternal sedation was achieved. Only mild respiratory acidosis was observed as a result of mild respiratory depression. In no mother apnoe occurred. All haemodynamic parameters, both foetal and maternal, remained stable during the procedure. Maternal sedation, respiratory depression and foetal immobilisation were quickly reversible following cessation of the remifentanil infusion.