Perinephric hematomas are common after percutaneous needle biopsy of the kidney and are usually clinically occult. Infectious complications in the absence of concomitant urinary tract infection, however, are unusual. A patient is reported who developed perinephric abscess (Streptococcus pneumoniae) at the site of a renal biopsy performed five years earlier. Wisdom tooth impaction and extraction occurred shortly after the biopsy. It is speculated that bacteremia of dental origin plus immunosuppressive therapy acted adjunctively to produce localization of infection in an area of previous trauma. Elective procedures that may induce transient bacteremia after percutaneous kidney biopsy may be hazardous and are best avoided. Antibiotic prophylaxis for such procedures should be considered.