Publisher Summary This chapter reviews the published work related to ultimate strength, covering the period 2000–2003. It demonstrates that the field is very active in academia as well among practicing engineers. The constant strive for more cost-effective structures at required levels of safety drives the work towards a better understanding of the connection between ultimate strength, loads, initial design, and in-service degradation. Many of the important real-life configurations show a complex dependence among these aspects, that there are plenty of opportunities for significant advances in the years to come. One of the challenges to be addressed is the way to efficiently deal with coupling between micro and macro mechanics. There are different methods that include: empirical, analytical, numerical, and experimental methods. Reliability analysis techniques have been continuously applied to different types of ships and offshore structures. Different structures are also explained in this chapter. An extensive sensitivity study— varying the most uncertain parameters— such as width of heat-affected zone, geometric imperfections and residual stresses— reveal that the ultimate strength is quite sensitive to quantities, which are typically considered of secondary importance in a steel structure.