The production of K⁺ and K⁻ mesons in elementary proton–proton collisions has been investigated at the Cooler synchrotron COSY in Jülich. A high quality proton beam with low emittance and small momentum spread permitted study of the creation of these mesons very close to the kinematical threshold.The energy dependence of the total cross section is investigated using internal beam facilities providing a high accuracy particle momentum determination as well as an external non-magnetic detection setup with a large geometrical acceptance. The determination of the four-momentum vectors for all ejectiles of each registered event gives the complete kinematical information allowing study of the interaction of the outgoing particles. Results on the performed studies of the pp → ppK⁺K⁻, pp → pΛK⁺ and pp → pΣ⁰K⁺ reactions will be presented and their relevance to the interpretation of heavy ion collisions will be discussed.