The histology of normal and regenerated optic lobes was examined in young specimens of Xenopus laevis by applying the Golgi-Cox method. In the operated animals the unilateral ablation of the optic lobe has been performed at the early larval stages (48-51) and at the later larval stages (55-56), according to Nieuwkoop and Faber. From our observations we drew the following conclusions: 1) The histological features of the optic tectum of Xenopus laevis are essentially similar to those of other Anurans. 2) When the unilateral ablation of the optic lobe is performed at stage 48 the restitution is morphologically and histologically complete: all the different neuronal types found in the control side were present also in the operated side. 3) When the operation is done at stage 51, although all the tectal neurons regenerate, an abnormal layering is observed in the operated lobe. 4) In the later stages (55 and 56) the regenerated lobe has always an aberrant structure and results in a small mass of nerve cells and fibres. The neurons are almost exclusively of the multipolar type; the piriform neurons are quite few and abnormally distributed. The small piriform neurons, the spindle-like cells and the horizontal cells are lacking.