We present transposition algorithms for matrices ahtat do not fit in main memory. Transposition is interpreted as a permutation of the vector obtained by mapping a matrix to linear memory. Algorithms are derived from factorizations of this permutation, using a class of permutations related to the tensor product. Using this p\formulation of transpotision, we first obtain several known algorithms and then we derive a new algorithms which reduces the numver of isk accesses required. The new algorithm was compared to exeisting algorithms using an implementaion on the intel iPSC/860. This comparison shows the benefits of the new algorithm.