Propionibacterium avidum is traditionallyconsidered an organism of lowpathogenicity and is seldom associatedwith human infection. Rare reports of breast abscess caused by P. avidumhave been almost exclusively associated with immunosuppression or prior surgicalintervention. There are a small numberof reports of this organism causing splenic abscess, septic arthritis, sacroiliitis,and osteomyelitis, as well as onereport of perianal abscess (1-5). All these infections occurred in immunocompromised patients, patients with pre-existing medical conditions, or followinga medical intervention (1-8). The organism has also been associated rarelywith breast abscess (6-8), with only onesuch case being reported in a previouslyhealthy individual who had no historyof prior surgical intervention (8). Because of its low growth rate, itis possible that infections with P. avidumare underreported. We report a caseof recurrent breast abscess caused byP. avidum that resulted from mammaryduct ectasia in the absence of immunosuppressionor prior surgery andpropose that the organism is an underrecognizedcause of such infections.