Prior imaging studies with ultrasound and CT have shown that bladder wall thickness (BWT), detrusor muscle volume (DMV) and prostate volume (PV) increase with age. We found a significant increase in DMV, BWT and PV when comparing males aged 30-39 to 60-69. There was no significant increase in BWT in females from the third to the sixth decade. While DMV increased significantly for women, the percent increase in muscle volume was substantially higher for men, likely the result of prostate hypertrophy. This is the first study, to our knowledge, to correlate physiologic changes of the urinary system in men and women using MRI.