Atosiban, the first member of a new tocolytic drug class, the ocytocin-receptor antagonists, has just been awarded marketing approval in Europe. The clinical effectiveness of atosiban is comparable to that of ritodrine, but atosiban is better tolerated with no evidence of significant maternal or fetal adverse effects. Maintenance therapy with atosiban cannot yet be envisaged due to the lack of a satisfactory formulation at the present time.