The binding and functional activity of the CC chemokines monocyte chemoattractant protein‐1 (MCP‐1), MCP‐2, and MCP‐3 have been characterized using Chinese hamster ovary DXB‐11 cells transfected with the chemokine receptor CCR2B. Receptor binding studies demonstrated that ¹²⁵I‐labeled MCP‐1 bound to a single class of high‐affinity receptors with a K_d of 0.14 (0.070.32) nM. In competition studies MCP‐1, MCP‐2, and MCP‐3 completely inhibited ¹²⁵I‐labeled MCP‐1 binding with K_i values of 0.3 (0.16‐0.46), 8.8 (3.4‐26), and 12.2 (0.6‐22) nM, respectively. In calcium mobilization studies, MCP‐1 and MCP‐3 induced robust elevations in intracellular calcium concentrations, whereas MCP‐2 was only weakly active. In contrast, using changes in extracellular acidification rate as a functional readout, all three chemokines were identified as potent agonists of CCR2B. These data demonstrate that MCP‐2, in addition to MCP‐1 and MCP‐3, is a potent agonist of CCR2B and furthermore that MCP‐2 activates either different or a subset of the signaling pathways activated by MCP‐1 and MCP‐3. J. Leukoc. Biol. 62:911–915; 1997.