Human airway epithelial cells (HAEC) constitutively express the CXC chemokine receptor, CXCR3, which regulates epithelial cell movement. In diseases like chronic obstructive pulmonary disease (COPD) and asthma, characterized by denudation of the epithelial lining, epithelial cell migration may contribute to airway repair and reconstitution. This study compared the potency and efficacy of three CXCR3 ligands, I-TAC/CXCL11, IP-10/CXCL10 and Mig/CXCL9, as inducers of chemotaxis in HAEC and the underlying signaling pathways involved. Studies were performed in cultured HAEC from normal subjects and the 16-HBE cell line. In normal HAEC, the efficacy of I-TAC-induced chemotaxis was 349 ± 88 % SEM of the medium control and approximately one-half the response to epidermal growth factor, a highly potent chemoattractant. In normal HAEC, Mig, IP-10, and I-TAC induced chemotaxis with similar potency and a rank order of efficacy of I-TAC = IP-10 > Mig. Pre-incubation with pertussis toxin completely blocked CXCR3-induced migration. Of interest, intracellular [Ca⁺²] did not rise in response to I-TAC, IP-10, or Mig. I-TAC induced a rapid phosphorylation (5-10 minutes) of 2 of the 3 mitogen activated protein kinases (MAPK), i.e., p38 and ERK1/2. Pre-treatment of HAEC with the p38 inhibitor, SB203580, or the phosphotidyl-3-inositol kinase (PI3K) inhibitor, Wortmannin, dose-dependently inhibited the chemotactic response to I-TAC. In contrast, the ERK1/2 inhibitor, U0126, had no effect on chemotaxis. These data indicate that in HAEC, CXCR3-mediated chemotaxis involves a G-protein, which activates both the p38 MAPK and PI3K pathways in calcium-independent fashion.