Introduction: Capsular contractures remain a well-recognized complication following the use of breast implants for both augmentation mammaplasty and breast reconstruction. A number of factors may be related to the development of clinically significant peri-prosthetic capsules (Grade 3 or 4, Baker classification). Contamination of the prosthesis at the time of insertion may cause a subclinical infection, and thus stimulate a chronic inflammatory response leading to the development of clinically significant capsules. Purpose: The purpose of this study was to determine if there is an association between capsule culture positivity, and capsular contractures (Grade III or IV, Baker classification). Methods: All women with breast implants or tissue expanders presenting for secondary breast surgery during the one year study period (June 2007 - June 2008) were included in the study. Intraoperatively, swab cultures were taken of each patient's skin surface, implant surface, and inner capsular wall. These swabs were examined for aerobic, anaerobic, mycobacterial, and fungal contaminants. Biopsies of the capsules were also sent for culture and sensitivity examination. Results: Throughout the 12 month study period, 39 women were recruited into the study. This cohort consisted of women undergoing tissue expander/implant exchange (56%), capsulotomy (33%), or other secondary procedures (15%). Women identified as having Grade 3 or 4 capsular contractures at the preoperative visit did not have a prior history hematoma, infection, or other significant complications. In the entire cohort, five women had culture positive capsules. The incidence of culture positivity in patients with capsular contractures was 22%. Culture positivity was associated with the diagnosis of clinically significant capsular contractures (p=0.011). Clinically significant capsular contractures were also associated with implant surface type (p=0.002), and implant pocket (p=0.008). Conclusions: In our study, culture positivity of implant capsules was associated with the presence of clinically significant capsules. Contamination of breast implants or tissue expanders at the time of insertion may contribute to the formation of capsular contractures.