Black lipid membranes (BLMs) are widely used for recording the activity of incorporated ion channel proteins. However, BLMs are inherently unstable structures that typically rupture within a few hours after formation. Here, stabilized BLMs were formed using the polymerizable lipid bis-dienoyl phosphatidylcholine (bis-DenPC) on glass pipettes of approximately 10 microm (I.D.). After polymerization, these BLMs maintained steady conductance values for several weeks, as compared to a few hours for unpolymerized membranes. The activity of an ion channel, alpha-hemolysin, incorporated into bis-DenPC BLMs prior to polymerization, was maintained for 1 week after BLM formation and polymerization. These lifetimes are a substantial improvement over those achievable with conventional BLM technologies. Polymerized BLMs containing functional ion channels may represent an enabling technology for development of robust biosensors and drug screening devices.