The crystal and magnetic structure of SmCo5 is determined by neutron powder diffraction between 5 K and the Curie temperature. In order to overcome the enormous neutron absorption of samarium, a 154Sm isotopically enriched sample was used. The ordered magnetic moments of both crystallographically distinct cobalt atoms are not significantly different over the whole temperature range. They decrease from 2.2 μB at 5 K to about 0.6 μB at 1029 K. Samarium's ordered magnetic moment decreases from 1.0 μB at 5 K, runs through a minimum of 0.2 μB around 650 K, and becomes larger than cobalt's ordered magnetic moment above 950 K. No sign or orientation change of the samarium and cobalt ordered magnetic moments is found between the Curie temperature and 5 K. SmCo5 is thus a ferromagnet and does not switch to a ferrimagnetic state as discussed in the literature.