To collect characteristics of patients with ADPKD across a broad population, over time to better understand disease progression (signs, symptoms and outcomes). Association with total kidney volume changes and other measures of disease progression will be determined in order to identify a population at increased risk for disease progression. The economic and quality life impact of ADPKD will be assessed. Subjects who terminated participation early from clinical trials with tolvaptan may also be followed.

Inclusion Criteria:

• existing diagnosis of ADPKD by modified-Ravine criteria
• Total kidney volume >= 300 cc/m height by ultrasound or >= 250 cc/m height by MRI

Exclusion Criteria:

• Current or expected (within the next six months) interventions for the treatment of ADPKD affecting kidney volume

Subjects will be identified by participating clinics (primarily nephrology clinics) treating patients with ADPKD.