Many of the potential effects of antihypertensive therapy, including renal function, have been inadequately investigated in clinical trials in older adults. In an observational study, we examined the association between treatment with various classes of antihypertensive agents and 3-year changes in serum creatinine in 1296 older adults with treated hypertension and without prior renal disease (mean age 72.2 years; 60% female; 30% diabetic; 42% with cardiovascular disease (CVD)) from the Cardiovascular Health Study. Baseline antihypertensive medications included thiazides (HCT), beta-adrenergic blockers, angiotensin converting enzyme inhibitors (ACE-I), calcium channel blockers (CCB), vasodilators (VAS), HCT + BB, HCT + ACE-I, HCT + CCB, HCT + VAS, loop diuretics (LOOP), and other combinations. Unadjusted results indicated that minimal changes in mean serum creatinine occurred over time for all therapies and only a few changes were statistically significant (HCT: +0.02 mg/dL, ACE-I: +0.04, CCB: +0.04; all P < .05; LOOP: +0.06 mg/dL; P < .001). In multivariate analyses with HCT users as the reference group and adjusting for baseline serum creatinine, age, sex, smoking, diabetes mellitus, CVD, height, weight, common carotid intima-media thickness, and use of allopurinol, phenytoin, cimetidine, and nonsteroidal antiinflammatory drugs, all of the relative changes were small and statistically nonsignificant except for HCT + VAS users (+0.07 mg/dL; P < .05). When users of the same therapy at baseline and follow-up were restricted, only LOOP users had significant albeit small changes in serum creatinine (+0.05 mg/dL; P < .05). Although results from clinical trials are needed to confirm these findings, these observational data suggest no major differences between specific antihypertensive therapies in 3-year serum creatinine changes in older adults without prior renal disease.