How reliable is office assessed blood pressure (BP) in chronic kidney disease (CKD) patients and kidney transplant (KTx) recipients is yet to be determined, although the diagnosis of arterial hypertension has been based on these measurements. The aim of this study was to investigate the potential differences between office assessed BP and ambulatory blood pressure monitoring (ABPM) in CKD patients and KTx recipients. We conducted a prospective study which enrolled 45 patients. Morning and evening seated office BPs were assessed using a sphygmomanometer at 5 consecutive outpatient visits. A mean systolic BP (SBP) and diastolic BP (DBP) was calculated. Ambulatory blood pressure was measured over 24 hours using a Meditech ABPM-05 device. Office SBP was statistically significant higher in CKD patients than KTx recipients both in the morning and evening (p=0.0433 and p=0.0066 respectively). ABPM showed higher night-time SBPs (p=0.0445) and higher overall, day-time and night-time DBPs in KTX recipients (p=0.0001, p=0.0006, p<0.0001 respectively). In CKD patients, office SBPs and DBPs are significantly higher than overall SBPs and DBPs as assessed by 24hr ABPM. Office BP monitoring as assessed by clinician is acceptable but tends to overestimate BP in both CKD and KTx study groups.