With the aim to determine the influence of reducing systolic blood pressure in urinary TGF-beta1 of type 2 diabetes (DM2) with diabetic nephropathy (DN), 21 subjects with type 2 diabetes and proteinuria >500 mg/24 h were studied. Amlodipine and ramipril were added to their previous antihypertensive treatment for 12 weeks. Urinary TGF-beta1 (UTGF-beta1) was determined at 0, 4, 8 and 12 weeks. Plasma TGF-beta1 was determined at 0 and 12 weeks. Subjects whose mean systolic blood pressure (SBP) during treatment were under 140 mmHg were grouped as the better SBP controlled group (n = 11) and those with SBP equal to or greater than 140 mHg were grouped in a moderate SBP controlled group (n = 10). Compared to baseline, mean log UTGF-beta1 at 4, 8 and 12 weeks decreased (-0.22 +/- 0.15 pg/mg; p = 0.04) in better SBP controlled group but not in the moderate SBP controlled group (-0.12 +/- 0.08 pg/mg, p = 0.82). Mean SBP correlated with UTGF-beta1 (r = 0.458, p = 0.0357), and this effect was independent of HbA1c (p = 0.042). By controlling SBP in DM2 subjects with DN we might decrease UTGF-beta1. We propose that reduction of UTGF-beta1 is due to a decrease in renal TGF-beta1 production.