A method and apparatus for automatically detecting and diagnosing lead-related conditions is provided. Specifically, relatively short-term and relatively long-term impedance parameters are determined for detecting an impedance trend indicative of a lead-related condition such as an open circuit, which may be due to a conductor fracture or poor connection to an associated implantable medical device, or a short circuit due to an insulation breach. Monitoring of multiple lead impedance parameters is performed to diagnose a lead-related condition based on a number of diagnostic criteria. Supplementary analysis of multiple lead impedance parameter trends may be performed to identify lead-specific conditions, such as metal ion oxidation induced insulation degradation. A lead-related condition diagnosis and supporting data are stored in memory for uplinking to an external device for review by a clinician. A recommended corrective action and/or a patient notification signal for a lead-related condition may optionally be provided.