Seven-transmembrane receptors are commonly coupled to multiple signaling pathways in cells. The simple model describing agonists for these receptors as producing a common active state to induce uniform activation of the pathways linked to the receptor has been shown to be untenable in light of a large body of data that suggest that some agonists produce activation of some but not all available pathways. These agonists are referred to as 'biased' in that they select which signaling pathways become activated upon binding to the receptor. The data to support this mechanism as well as ideas on the possible therapeutic application of this effect will be discussed.