Background: Hypertension is prevalent in chronic kidney disease (CKD), but the control of hypertension is suboptimal. We reported the prevalence and characteristics of resistant and undertreated hypertension based on a nationwide survey aiming to improve blood pressure (BP) control. Methods: Resistant hypertension (RH) was defined as BP above the target (<140/90 mm Hg) despite the use of 3 antihypertensive drugs or achieving the target BP by using >= 4 antihypertensive drugs. Undertreated hypertension was defined as uncontrolled hypertension (unCH) using <= 2 drugs. We compared the characteristics and antihypertensive treatment among different groups (including RH and unCH using <= 2 drugs). Multivariable logistic regression was used to detect factors associated with unCH using <= 2 drugs and RH. Results: 4,435 nondialysis CKD patients with hypertension were analyzed, and 36.9% of participants achieved controlled hypertension (CH) using <= 3 drugs, 11.1% met the criteria for RH, and 52% had unCH despite the use of <= 2 antihypertensive drugs. Participants with unCH using <= 2 drugs had low usage of renin-angiotensin system blockers (36.8%) and diuretics (5.5%), which was much lower than participants with CH using <= 3 drugs and RH (P< 0.05). After multivariable adjustment, obesity, advanced CKD stages, urinary protein level of >= 1.5 g/24 h, diabetes, and cardiovascular disease were associated with RH in CKD patients (P< 0.05). Conclusion: Compared with RH, undertreated hypertension contributes more to the unCH in Chinese CKD patients. It is important to ensure adequate antihypertensive treatment, including choosing antihypertensive drugs, that guidelines recommended.