During the last two decades, a rapid progress has been made in the development of analytical methods for a fire engineering design of load bearing and separating structures and structural members. Consequently, more and more countries are now permitting a classification of structural members with respect to fire to be formulated analytically as an alternative to the internationally prevalent method of classification based on results of standard fire resistance tests. In a longterm perspective, the development goes towards an analytical design, directly based on a natural fire exposure, specified with regard to the combustion characteristics of the fire load and the geometrical, ventilation and thermal properties of the fire compartment. Parallel to this progress, a further development is going on towards a reliability based structural fire engineering design. The development includes contributions related to a practical design format calculation, based on partial safety factors, as well as to an evaluation, based on first order reliability methods. The paper describes and comments on these developments.