Recent progress in chromium and iron doped II-VI semiconductor materials makes them the laser sources of choice when one needs a compact system with tunability over 1.9-5.1 μm. Output powers exceeding 10W and efficiency up to 70% were demonstrated in several Cr doped semiconductors. The unique combination of technological (low-cost ceramic material) and spectroscopic characteristics makes these materials ideal candidates for mid-IR tunable laser systems. This article reviews transition metal doped II-VI materials and recent progress in Cr- and Fe-doped solid-state mid-IR lasers. © 2010 by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.