Transparent oxyfluoride glass ceramics containing NaYF4:Er3+ nanocrystals have been prepared by melt quenching and subsequent thermal treatment. X-ray diffraction and high-resolution transmission electron microscopy analysis confirmed the precipitation of NaYF4 nanocrystals in glass. Energy dispersive spectrometer results evidenced the preferential concentration of Er3+ ions in nanocrystals. Mid-infrared, upconversion, and near-infrared emissions were measured upon excitation with 980 nm laser diode and the luminescence mechanisms were discussed. Intense 2.711M emission originating from the Er3+:I-4(11/2) -> I-4(13/2) transition was achieved due to the incorporation of Er3+ ions into the precipitated low phonon energy fluoride nanocrystals. The results indicate that oxyfluoride glass ceramic containing NaYE4:Er3+ nanocrystals is a promising candidate material for 2.7 mu m laser. (C) 2015 Elsevier Ltd. All rights reserved.