Given a virtual link diagram D, we define its unknotting index U (D) to be minimum among (m, n) tuples, where m stands for the number of crossings virtualized and n stands for the number of classical crossing changes, to obtain a trivial link diagram. By using span of a diagram and linking number of a diagram we provide a lower bound for unknotting index of a virtual link. Then using warping degree of a diagram, we obtain an upper bound. Both these bounds are applied to find unknotting index for virtual links obtained from pretzel links by virtualizing some crossings.2010 Mathematics Subject Classification. Primary 57M25; Secondary 57M90.