An intensive development effort is going on throughout the world, in order to develop reliable lasers emitting in the 3 μm wavelength range, as this wavelength is strongly absorbed by the water and the other components of soft and hard tissue and thus its use is important in various medical applications. In parallel, good flexible delivery systems, in the mid-IR wavelength region, are needed in order to deliver the laser beam to the tissue. In this work High Power (HP) Oxide Glass fibers are tested for determining their maximum capabilities in delivering free-running and Q-switched Er:YAG laser radiation at 2.94 μm. Oxide glass is a new material in solid core fiber fabrication for medical applications, and its performance at the wavelength of 2.94 μm, for various laser characteristics is of great importance. Also a comparison is made between results obtained with the two different Er:YAG lasers, afree-running and a Q-switched one, and the results obtained at 2.78 μm, with a chemical HF laser.