Transition-metal phosphides (Co2P, Ni2P, MoP, WP, CoMoP, NiMoP) were prepared by reducing metal oxide/phosphate precursors in a flow of H2. The solids obtained were tested in the hydrodenitrogenation of o-propylaniline at 643 K and 3 MPa. All the catalysts were active, with product selectivities resembling those of sulfidic catalysts. The influence of H2S on the activity and selectivities was tested and is discussed with regard to a possible surface modification. Based on the surface area of each catalyst, we estimated the relative intrinsic activities of the different phosphides. According to this estimation, MoP was intrinsically the most active catalyst.