This paper describes how probabilistic fracture mechanics calculations have been used to assess the notional probability of fracture of a number of crack-like weld defects in an offshore structure. The results were used in a decision making context to establish a rational repair sequence, so that the defects could be repaired on an order-of-merit basis. This was necessary in order to minimize risks because of the possibility of the repair programme being curtailed, for instance, by bad weather. The analysis procedure, which is based on the probabilistic treatment of a standard deterministic fracture model, could be applied in any similar situation where appropriate information is available. An important new aspect is the way in which fracture probabilities are assessed for defects which are large compared with the size of fracture toughness test specimens.