Abstract In this paper, we introduce the centroid and generalized centroid of a type-2 fuzzy set (both of which are essential for implementing a type-2 fuzzy logic system), and explain how to compute them. For practical use, we show how to compute the centroid of interval and Gaussian type-2 fuzzy sets. An exact computation procedure is provided for an interval type-2 set, whereas an approximation is provided for both interval and Gaussian type-2 sets. Examples are given that compare the exact computational results with the approximate results.