Résumé : A search for charmed particles (D mesons, D* mesons and λc baryons) produced in pp interactions at 12 GeV/c incident beam momentum has been carried out using 16 500 events with a visible V0 decay in a 10 event/μb experiment in BEBC. No enhancements are observed in the invariant mass distributions of Ks0 + nπ (n = 1-5) and λ(λ) + nπ (n = 1-3) in the regions of the known charmed particle masses. The upper limits for the product of the inclusive production cross sections times decay branching ratios of D, D* and λc particles as well as the production of pairs of charmed mesons are calculated at 95% confidence level. The Ks0 yields per annihilation event in e+e- and pp interactions are compared at various energies. © 1978.