By the result of Deligne, Griffiths, Morgan and Sullivan, the Malcev Lie algebra of the fundamental group of a compact Kahler manifold is quadratically presented. In this talk, we consider the fundamental groups of compact Sasakian manifolds. We show that the Malcev Lie algebra of the fundamental group of a compact 2n+1-dimensional Sasakian manifold with $n \ge2$ admits a quadratic presentation by using Morgan's bigradings of Sullivan's minimal models of mixed-Hodge diagrams.