Fibroblasts maintain the structural framework of animal tissue by synthesizing extracellular matrix molecules. Chronic lung diseases are characterized in part by changes in fibroblast numbers, properties, and more. Fibroblasts respond to a variety of growth factors, cytokines, and proinflammatory mediators. However, the signaling mechanisms behind these responses have not been fully explored. We sought to determine the role of Ca²⁺ waves in transforming growth factor–β (TGF-β)–mediated gene expression in human pulmonary fibroblasts. Primary human pulmonary fibroblasts were cultured and treated with TGF-β and different blockers under various conditions. Cells were then loaded with the Ca²⁺ indicator dye Oregon green, and Ca²⁺ waves were monitored by confocal [Ca²⁺]_i fluorimetry. Real-time PCR was used to probe gene expression. TGF-β (1 nM) evoked recurring Ca²⁺ waves. A 30-minute pretreatment of SD 208, a TGF-β receptor–1 kinase inhibitor, prevented Ca²⁺ waves from being evoked by TGF-β. The removal of external Ca²⁺ completely occluded TGF-β–evoked Ca²⁺ waves. Cyclopiazonic acid, an inhibitor of the internal Ca²⁺ pump, evoked a relatively slowly developing rise in Ca²⁺ waves compared with the rapid changes evoked by TGF-β, but the baseline fluorescence was increased. Ryanodine (10⁻⁵ M) also blocked TGF-β–mediated Ca²⁺ wave activity. Real-time PCR showed that TGF-β rapidly and dramatically increased the gene expression of collagen A1 and fibronectin. This increase was blocked by ryanodine treatment and cyclopiazonic acid. We conclude that, in human pulmonary fibroblasts, TGF-β acts on ryanodine-sensitive channels, leading to Ca²⁺ wave activity, which in turn amplifies extracellular matrix gene expression.