  We study the flavor structure in intersecting D-brane models. We study
anomalies of the discrete flavor symmetries. We analyze the Majorana neutrino
masses, which can be generated by D-brane instanton effects. It is found that a
certain pattern of mass matrix is obtained and the cyclic permutation symmetry
remains unbroken. As a result, trimaximal mixing matrix can be realized if
Dirac neutrino mass and charged lepton mass matrices are diagonal.
