[en] We investigate the reactions πN → a₀N and pp → da₀⁺ near threshold and at medium energies. An effective Lagrangian approach is applied to analyse different contributions to the cross section of the elementary reaction πN → a₀N. It is known that the a₀ couples quite strongly to the channels πη and πf₁(1285). Therefore, for the t-channel contribution to the πN → a₀N transition amplitude we took into account the exchanges of η(550) and f₁(1285)-mesons. The a₀πη and a₀πf₁ coupling constants were calculated using the following experimental values of the partial widths: Γ_a0→πη = 80 MeV and Γ_f1→a0π ≅ 8.2 MeV. The parameters of the ηNN, f₁NN and a₀NN vertices are taken from literature. We consider also the s and u-channel diagrams with a nucleon in the intermediate state. These results are used to calculate the differential and total cross sections of the reaction pp → da₀⁺ within the framework of the two-step model in which two nucleons produce an a₀-meson via π -meson exchange and fuse to a deuteron. It is found that the main contribution comes from the u-channel diagram for the elementary amplitude πN → a₀N. The forward pp → da₀⁺ differential cross section is about 120 nb/sr at T_lab = 2.6 GeV. This value of the cross section makes the corresponding experiment at COSY quite feasible. (orig.)