Staphylococcus aureus ATCC 6538P is auxotrophic tor proline. Under conditions of proline starvation, the organism synthesizes a transport system thus greatly increasing the rate of transport of proline into the cell. The proline transport systems of both the starved and unstarved cells were shown to be enzymatic, energy dependent, and specific for L-proline. Protein synthesis was required for derepression, and when the cells were fully induced, the organism established a non-exchangeable pool for proline, whose maintenance was dependent on protein synthesis. It is proposed that this transport system serves as a scavenging mechanism when the organism is in an environment deficient in proline.