Rationale: Despite increasing recognition of BMP signalling in tissue remodelling the expression pattern of ligands and signalling pathways remain undefined in the asthmatic airway. Objectives: To determine expression of BMP ligands (BMP-2, 4 and 7) and Type I and Type II receptors (ALK-2, ALK-3, ALK-6 and BMPRII) as well as evidence for activation of BMP signalling via detection of phosphorylated (p)Smad1/5 expression in asthmatic airways at baseline (compared to non-asthmatic controls), and after allergen challenge. Methods: Bronchial biopsies were obtained from 6 non-asthmatic control volunteers, and 15 atopic asthmatics (median age 25 years, median FEV₁% predicted 97%) at baseline, then at 24 hours and 7 days after allergen challenge. Expression of BMP ligands, receptors and signalling was analysed using immunohistochemistry. Results: BMP ligand expression did not differ between asthmatic and control airways at baseline. Compared to the normal airway there was significant down regulation of ALK- 2 (p=0.001), ALK-6 (p=0.0009) and BMPRII (p=0.009) expression in asthma. Allergen challenge was associated with marked and sustained up-regulation of BMP-7 in airway epithelium (p=0.017) and infiltrating inflammatory cells (p=0.071) (predominantly in eosinophils, but also CD4⁺ T cells, mast cells and macrophages). Up-regulation of pSmad1/5 expression (p=0.031), ALK-2 (p=0.002) and ALK-6 (p<0.001) was observed indicating active signalling. Conclusion: BMP receptor expression is down-regulated in the asthmatic airway which may impede repair responses. Allergen provocation increases expression of the regulatory ligand BMP-7, activates BMP signalling and increases receptor expression all of which may contribute to repair and control of inflammation.