Texture, microstructure and mechanical properties of low carbon microalloyed steel bars control-rolled in an oval/round process have been studied. Strength can be increased by decreasing rolling temperature without significant ductility loss. This can be explained in terms of microstructural refinement as well as ferrite work hardening by rolling in γ/α duplex phase region. Ductile/brittle transition temperature (_VT_S) in Charpy impact test is also remarkably decreased by lowering rolling temperature, e.g., _VT_S<-196°C for the material with the finishing rolling temperature of 644°C. Such a marked improvement of toughness mostly arises from the refinement of microstructure, although a significantly strong texture development promotes the occurrence of separations as well. The main and suborientations of texture developed are an unusual {100} <001> and a {111} -{211} <011>, respectively. Fractographic examinations revealed that cleavage cracks either perpendicular to rolling direction or parallel to the rolling planes initiate within relatively coarse grains of the cube orientation elongated in the rolling direction and that the propagation of such cracks is arrested by the surrounding extremely fine grained area of different orientations such as {111}-{211}<011>. The initiation of separations cannot be explained by the Chao's plastic anisotropy model.