Background: In chronic kidney disease (CKD), anemia and hypertension are significant co-morbidities that contribute to cardiovascular and renal disease progression. Objective: The purpose of the study was to identify correlations between changes in hematologic variables against markers of renal function, blood pressure, and erythropoietin (EPO) in a naturally occurring hypertensive model of CKD, the Lewis polycystic kidney (LPK) rat. Methods: Complete blood count, systolic blood pressure, urea and creatinine concentration, urinary protein to creatinine ratio, and plasma EPO concentration were determined in control Lewis (n = 51) and LPK rats (n = 56) aged 6-24 weeks. Renal EPO gene expression and RBC osmotic fragility were also documented. Hematopoiesis in spleen and bone marrow were assessed. Results: Lewis polycystic kidney rats had increasing urea and creatinine concentrations, concurrent with the development of a nonregenerative normocytic/normochromic anemia and hypertension, with a significant negative correlation between both HGB and HCT with urea concentration and blood pressure (P