In the perioperative management of patients on long-term oral anticoagulant (OAC) therapy the problem is balancing the thromboembolic (TER) and the haemorrhagic risk (HR) in the perioperative period. The Federazione Centri per la diagnosi della trombosi e la Sorveglianza delle terapie Antitrombotiche (FCSA) activated an online registry from November 2001 to August 2003 in order to collect information on the management of these patients in Italy. Four hundred and eleven patients, undergoing elective major (18%) and minor surgery (82%), from 7 centres, were registered. Three hundred and ninety-nine out of 411 patients received LMWH either once a day (310 patients) or twice a day (89 patients) during OAC therapy discontinuation. Two thromboembolic (0.48%) and 16 bleeding events (7 major; 1.7%) were reported. Notwithstanding the lower doses of heparin (54.3 U/kg o.d. and 64.4 U/kg b.i.d.), the thromboembolic complications are in line with those reported in the literature. The data of this study suggest that the intervention with LMWH may be relevant only in the high-risk patients as already proposed by others.