α-Adrenergic blockers are potential alternative antihypertensive agents for diabetic patients. Data on their relative efficacy and their effect on kidney function and albuminuria are very limited however. 76 patients with diabetes type 2, hypertension (≧140/90 mm Hg) and albuminuria (≧30 mg/24 h) were randomized into three groups to receive cilazapril (2.5–10 mg), doxazosin (2–8 mg) or both. Patients of the first and second groups received a single agent for 4 months, the agents were then crossed for an additional period of 4 months followed by the addition of hydrochlorothiazide (25 mg) for a third 4-month period. Blood pressure was monitored monthly, creatinine clearance and HbA1c were measured before and at the end of each treatment period. Patients of the third group received reduced doses of cilazapril and doxazosin for 4 months. Hydrochlorothiazide was then added for the subsequent 4 months. There was a significant decline in blood pressure values during the first period in all groups. Cilazapril: systolic blood pressure (SBP) 160 ± 6 to 149 ± 5 mm Hg; diastolic blood pressure (DBP): 101 ± 3 to 94 ± 3 mm Hg (p = 0.001). Albuminuria declined from 350 ± 105 to 205 ± 96 mg/24 h (p = 0.001), creatinine clearance (CrCl) was unchanged. Doxazosin: SBP: 160 ± 7 to 151 ± 6 mm Hg; DBP: 97 ± 4 to 90 ± 4 mm Hg (p = 0.001). Albuminuria 373 ± 121 to 322 ± 107 mg/24 h (p = 0.065) and CrCl 87 ± 7 to 91 ± 6 ml/min. The combination of both agents at half doses was equipotent or superior to either drug alone. Cross-over of cilazapril and doxazosin reproduced the hypotensive effect and reversed the antialbuminuric effect. The addition of hydrochlorothiazide resulted in a further decline of 6–14 mm Hg in SBP and 3–11 mm Hg in DPB.