Between 2002-2006, the prospective Chronic Renal Insufficiency Cohort (CRIC) Study enrolled >3400 adults with chronic kidney disease to address overarching goals of identifying predictors of rapid progression of kidney disease and clarifying the relationship between kidney dysfunction and the risks of sub-clinical and clinical cardiovascular events, death, and resource utilization through an initial 5-year follow-up. The proposed CRIC-2 extended follow-up through to June 30, 2012 offers a unique opportunity to leverage the existing effort and success of CRIC-1 to establish a cohort of participants with chronic kidney disease who have long-term prospective follow-up on progression of kidney disease and a variety of different outcomes. This unparalleled resource will also expand the science related to chronic kidney disease natural history as well as the impact on cardiovascular disease and other adverse events. Specific Aims to be addressed by the Kaiser Permanente of Northern California/UCSF Clinical Center are: Aim 1. To re-enroll a high percentage of participants into CRIC-2 extended follow-up and maintain high retention rates throughout the study. Aim 2. To collect exposure and outcome data per the CRIC Phase 1 and 2 protocols. Aim 3. To obtain, process and transfer biospecimens to the CRIC laboratory and NIDDK biorepository. Aim 4. To investigate self-reported clinical events and obtain supporting medical records and documentation for adjudication of study outcomes. Aim 5. To implement local quality assurance and quality control procedures in order to obtain standardized, high quality data. Aim 6. To monitor routinely data collection, data management and follow-up rates. Aim 7. To participate proactively in governance and oversight of the CRIC Study through study-wide committees and related functions. Aim 8. To contribute to and participate in publishing and presenting findings from the CRIC Study. Aim 9. To promote and support the established CRIC Study Ancillary Studies Program, including collaboration with the broader nephrology research community.