Castleman's disease (CD) is a rare lymphoproliferative disorder with clinical features and prognostic factors that are incompletely characterized. This retrospective single-center study reviewed the largest HIV-negative CD patient cohort (n = 145) to date. By clinical classification, we identified 69 patients (47.6%) as unicentric CD (UCD) and 76 patients (52.4%) as multicentric CD (MCD). Pathological classification identified 74 patients (51.0%) with the hyaline-vascular variant, 51 patients (35.2%) with the plasma-cell variant, and 20 patients (13.8%) with a mixed variant. After a median follow-up duration of 58 months (range, 1-180 months), the 1-year and 5-year survival rates were 95.1% and 91.0%, respectively. UCD patients exhibited significantly better survival (1-year and 5-year survival rates of 98.5% and 97.1%, respectively) compared with MCD patients (1-year and 5-year survival rates of 92.1% and 85.5%, respectively; p = 0.005). By univariate and multivariate Cox regression analyses, the estimated glomerular filtration rate < 60 ml/min (with the MDRD equation; hazard ratio = 4.60; 95% confidence interval, 1.50-14.12; p = 0.008) was clinically significant and represented an independent predictor for death in MCD patients. In summary, this large-scale study suggests that UCD patients enjoy better survival than MCD patients and that renal function is an important prognostic factor for MCD patients.