This chapter discusses different ways in which one can use the frequencies to determine stellar properties. It considers straightforward comparisons of observed frequencies with those of stellar models, as well as the limitations and challenges of such comparisons. Different approaches are used to model stars whose frequencies have been observed. Some methods are similar to what is done if only the nonseismic properties of a star are known. Other methods make use of the fact that the average asteroseismic data give a good indication of the mass and radius of the star being modeled, and so these methods construct models around that mass and radius. Yet other methods involve optimization schemes. However, even the most complex optimization schemes used thus far do not explore the effects of all inputs and parameters that can be varied while constructing stellar models.