Risk analysis and structural reliability methods have reached the stage where they can help select design criteria and aid in developing code safety factors for offshore structures. The need to calibrate reliability models with an experienced data base suggests, however, that these techniques will only gradually be incorporated into practice and in a manner transparent to routine design decision-making. Complex structures require system reliability analyses to properly model extreme damage occurrences rather than the serviceability limits usually controlling land-based structures. Balanced reliability (safety indices) among competing failure modes can lead to more economical designs. A risk methodology can consistently treat a variety of hazards or environmental threats. The relative statistical and modelling uncertainties should be recognized and thus limit interpreting risk values in publically understood actuarial terms. Cost optimization using mathematical programming may be helpful in balancing risks but constraints on loss of life should be separately considered. A comparison is helpful with similar land-based industrial activities or other methods of fuel generation such as nuclear power or fossil fuel (coal).