Let M denote a compact, oriented n-mamfold of class C2 and let TM denote the tangent bundle of M. A vector jield on lW is a Cl cross section m TM, and afohztion is an integrable, orientable, Cl vector subbundle of TM. The basic properties of manifolds, vector fields, and vector bundles are described in [3, Chaps. II-VI], and the basic properties of foliations are described in [2]. A vector field 5 is tangent to a foliation % if [ is a cross section in 9 which is never zero. In this paper, basic properties of tangent vector fields to 2-dimensional foliations of 3-manifolds are studied. In the first section, the relevant obstruction theory for tangent vector fields to foliations is reviewed. Since integrability does not enter, these obstructions are precisely the obstructions for nonzero cross sections of tangent plane fields. In computmg these obstructions, it is clear that the topology of M and of the leaves of F must enter the considerations. For example, a necessary condition for a foliation of a 3-manifold to have a tangent vector field is that every compact leaf be a torus. General theorems relating the homotopy classes of nonsingular vector fields on the torus to their qualitative properties have been obtained by B. L. Reinhart [7]. These results are reviewed in the second section. It follows from the continuity of the foliation and the vector field, that Reinhart’s conditions impose constraints on vector fields tangent to leaves which spiral to the tori. In Section 3, these constraints are described in terms of the winding numbers of the vector field along certain curves. From these considerations, global qualitative properties of the vector field can be deduced. Applications are made to Reeb components and the Reeb foliations of the 3-sphere. For example, it is shown that every tangent vector field to a Reeb foliation has at least two periodic solutions, they are unknotted, and every pair of periodic solutions links once.