Differential torsion theories are introduced and it is shown that for a hereditary torsion theory every derivation on an R-module M has a unique extension to its module of quotients if and only if is a differential torsion theory. Dually, we show that when is cohereditary, every derivation on M can be lifed uniquely to its module of coquotients.The purpose of this paper is to introduce the concept of a differential torsion theory on Mod R and to use this notion to study derivations on modules and their extension to modules of quotients. After obtaining the main result concerning such extensions we turn our attention to the problem lifting derivations on modules to modules of coquotients.Throughout R will denote an associative ring with identity, all modules will be unitary right R-modules and Mod R will denote the category of unitary right R-modules. A functionIf is a derivation on R and M is an R-module, then a function d :for all x, y ∈ M and all a ∈ R. We now assume that is a fixed but arbitrary derivation on R and that every derivation under consideration is a -derivation. Also, if N is a submodule of an R-module M, then for any x ∈ M, (N : x) will denote the right ideal of R given by {a ∈ R | xa ∈ N }.