The purposes of this paper are five-fold to discuss: (1) when item response theory (IRT) equating methods should provide better results than traditional methods; (2) which IRT model, the three-parameter logistic or the one-parameter logistic (Rasch), is the most reasonable to use; (3) what unique contributions IRT methods can offer the equating process; (4) what work has been done that relates to the confidence that can be placed in the IRT equating results; and (5) what unresolved issues exist in the application of IRT to equating. Several issues are discussed to provide a background: formal definitions and requirements of equating; the basic principle of IRT equating; procedures for linking parameter estimates and deriving estimated true and observed score equatings using IRT; the practical advantages to be gained from using IRT equating; and the important distinction between test development and test analysis activities. (Author/BW)