Autosomal dominant polycystic kidney disease (ADPKD) is the most common hereditary disorder in kidneys characterized by the development of large fluid-filled kidney cysts, resulting in a progressive loss of function in the fifth to sixth decades and by the age of 70 leads to end-stage kidney disease (ESKD) in about 50% of patients. Mutations in two genes, and , that are known to cause ADPKD, account for 85% and 15% of cases, respectively. ADPKD shows highly variable clinical features, especially in progression to ESKD. Recently, tolvaptan that can delay the progression of kidney disease has been approved and it has become more important to define patients whose kidney disease progresses rapidly. Subclasses on the basis of annual height-adjusted total kidney volume (TKV) growth rate estimated from patient age, represented by the Mayo Imaging Classification, is recognized as a biomarker that can reflect the course of the disease. Mayo Imaging Classification can estimate rate of TKV growth and predicts future GFR decrease in typical ADKD. Clinical factors such as the rate of estimated glomerular filtration rate decline, hypertension before 35 years of age, and first urologic event before 35 years of age are also the factors those can predict kidney disease progression. ADPKD genotype affects the kidney disease outcomes. Patients with the PKD1 mutation have a more aggressive course than those with the PKD 2 mutations. Furthermore, the PKD1 patients with mutations that truncate the protein have higher risk of ESKD and death than those with nontruncating mutations or PKD 2 mutations. Although ADPKD genotype is related to the severity of the disease, genetic analysis is not widely used in clinical practice due to the lack of a standardized method and its high cost. In this time, the characteristics of rapid progressor patients who are indicated for tolvaptan administration and the ADPKD genotype that affects the severity of the disease will be presented