Dr. Gustavo Diaz-mercado is a urologist practicing in Miami Beach, FL. Dr. Diaz-mercado specializes in diseases of the urinary tract and the male reproductive system. This includes areas of the bladder, urethra, kidneys, penis and prostate. Urology is a surgical specialty and requires knowledge in other areas of expertise such as gynecology and internal medicine due to the variety of clinical problems that are involved.