The study of phase transitions in a three-dimensional weakly diluted 5-state Potts model is carried out by computer modeling. Systems with linear sizes L × L × L = N, L = 10 ÷ 40 at a spin concentration p = 1.00, 0.90 are considered. The obtained numerical data indicate that the introduction of an insignificant disorder in the form of non-magnetic impurities (p = 0.90) in the three-dimensional 5 - state Potts model is not essential for a phase transition of the first order.