The present invention concerns the use of an active ingredient selected from the group consisting of agonists of the adenosine receptor system, for inhibiting viral replication in cells. In particular, the invention provides a composition and method for inhibiting viral replication in cells, the method comprising presenting to the cells an effective amount of the active ingredient. According to one embodiment, the adenosine agonist is an A3 receptor agonist (A3RAg). The invention is particularly useful, for although not limited to, inhibiting the replication of HIV virus in human cells.