Green and red up-conversion emissions centred at 555 and 681 nm, respectively were investigated in LaCl 3 :U 3 + . They were observed after IR excitation in resonance with transitions between excited states. The green 2 K 1 5 / 2 -> 4 I 9 / 2 emission is excited via two different processes and the red 4 F 9 / 2 -> 4 I 9 / 2 one via one excited state process only. Excitation paths of these emissions as well as possibilities of a two-photon absorption and an avalanche up-conversion in this material are discussed.