Bacillus subtilis are Gram–positive rod shaped bacteria capable of rapid and coordinated group movement over a semi-solid surface, called swarming. Synthesis of flagella and surfactin are essential for successful bacterial swarming. Surfactant surfactin is secreted into the medium and is therefore classified as public good that can be used by others, including cheaters which do not contribute to the production of public goods. It was observed that B. subtillis can distinguish between highly related and less related strains by kin discrimination. Non-kin strains are swarming separately on the surface, while the related kin strains colonize the surface in a common swarm, which could limit the cross-use of public goods. It is not known whether kin discrimination affects the mutual sharing of public goods, such as surfactin, which we have studied in this master's thesis. Recombinant strains labeled with fluorescence proteins were prepared and then mixed and inoculated on B-medium. The surface colonization success of both strains was evaluated by fluorescence stereomicroscopy. We found that kin strains can effectively share surfactin with srfAA mutants and therefore colonize the entire agar surface together. Complementation was significantly less successful between non-kin strains, due to strong antagonism, and therefore the surface was mostly occupied by only one strain. Which strain occupied the surface was dependent on the ratio between the strains in the initial inoculum and the survival of an attack by another strain. We have shown that srfAA mutants can swarm when supplemented by a conditioned medium of a non-kin or kin strain. It was also observed that hag mutants, which do not produce flagella and therefore cannot swarm, share their surfactin with kin srfAA mutants, but with non-kin only when both strains survived and covered the surface area in spatially separated swarms. The sharing of surfactin is effective between related strains, while among less related strains, it is ineffective due to the mutual exclusion of strains. The differences between the effectiveness of surfactin secreted by kin or non-kin strains were not detected. We can conclude that kin discrimination limits the exploitation of public goods among non-kin strains.