New rare-earth trifluorides of Gd1-xYbxF3 crystals were grown using the micro-pulling-down (mu-PD) method and single crystals were obtained for composition of x between 0.12 and 0.42 in the current study. Neither visible inclusions nor cracks were observed. Room temperature up-conversion luminescence spectra of Praseodymium (Pr3+)-doped Gd1-xYbxF3 were studied. Visible Pr3+ emission was obtained under infrared laser pumping on the ytterbium (Yb3+) absorption broadband at 935.5 nm. The origin of this emission will be discussed as a function of the decay times. (c) 2006 Elsevier B.V. All rights reserved.