Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)We show that given a G-structure P on a differential manifold M, if the group G(M) of automorphisms of P is large enough, then there exists the quotient of a stochastic flows phi(t) by G(M), in the sense that phi(t) = phi(t) o rho(t) where xi(t) is an element of G(M), the remainder rho(t) has derivative which is vertical, transversal to the fibres of P. This geometrical context generalises previous results where M is a Riemannian manifold and phi(t) is decomposed with an isometric component, see [12] and [15], which in our context corresponds to the particular case of an SO(n)-structure on M.122Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)CNPq [302.704/2008-6, 480.271/2009-7, 142655/2005-8, 306.264/2009-9]FAPESP [07/06896-5]