Modified Conjugated Diene-Based Polymer and Rubber Composition Including the Same

A modified conjugated diene-based polymer and a rubber composition including the same are disclosed herein. In some embodiments, a modified conjugated diene-based polymer satisfying the conditions of i) a mooney viscosity from 75 to less than 100, measured in accordance with ASTM D1646 at 110° C., ii) a mooney stress relaxation ratio 0.4 or less, measured at 110° C., iii) a weight average molecular weight (Mw) of 750,000 g/mol or more, and iv) a molecular weight distribution from 1.0 to 2.0, wherein the molecular weight distribution is a ratio of Mw to the number average molecular weight (Mn).