Cerebrospinal fluid (CSF) has become a matrix for biomarker discovery and development in recent years. A number of biomarkers for pathogenic processes in Alzheimer's disease have been identified. Studies have revealed the diagnostic potential of CSF amyloid-beta, tau and phosphorylated tau levels. California Clinical Trials has conducted a number of studies in collaboration with drug developers that demonstrate the importance of CSF amyloid-beta peptides as biomarkers for drug development. These studies also establish the utility of CSF sampling via continuous indwelling lumbar catheterization (dynabridging) for assessing pharmacokinetic and pharmacodynamic parameters in conjunction with biomarker analysis. Corroborative approaches using multiple biomarker methods including neuroimaging and CSF biomarkers will provide a complete picture of the Alzheimer's disease brain.