Microalbuminuria is an early marker of diabetic nephropathy and its prevention is considered key for the primary prevention of diabetic nephropathy. Angiotensin-converting enzyme (ACE) inhibitors and nondihydropyridine calcium channel blockers (CCBs) have specific renoprotective properties in diabetes, and preliminary evidence is available that they are more effective in combination than either of the two agents alone in limiting albuminuria either in micro- or macroalbuminuric type 2 diabetic patients. The BErgamo NEphrologic DIabetes Complications Trial (BENEDICT) is a prospective, randomized, double-blind parallel-group study primarily aimed at evaluating the possibility of preventing the progression to microalbuminuria (urinary albumin excretion [UAE] rate 20-200 microg/min, i.e., incipient nephropathy) in 1209 hypertensive, type 2 diabetic patients with a normal UAE rate (<20 microg/min). During phase A of the study, patients are randomized to a 3-year treatment with one of the following: (1) a nondihydropyridine CCB (verapamil SR 240 mg/day); (2) an ACE inhibitor (trandolapril 2 mg/day); (3) the combination of the above study drugs (verapamil SR 180 mg/day plus trandolapril 2 mg/day); or (4) placebo. Phase B of the study evaluates the progression to macroalbuminuria (UAE> or =200 microg/min) in patients who progress to microalbuminuria in phase A or are found with microalbuminuria during the screening phase; these patients are randomized to a 2-year treatment with either trandolapril (2 mg/day) alone or verapamil SR (180 mg/day) plus trandolapril (2 mg/day). BENEDICT final results are expected to be available by the end of 2003 for phase A and 2 years later for phase B. The BENEDICT study, in addition to exploring whether primary prevention of diabetic nephropathy is an achievable goal, will also offer an opportunity to study prospectively risk factors of nephropathy and other chronic complications of type 2 diabetes. Here we provide an overview of the protocol and summarize the main baseline demographic, biochemical, and clinical characteristics of randomized participants.