Chest wall irradiation decreases locoregional recurrence and breast cancer-related mortality in women at high risk for recurrence after mastectomy. Many women undergoing mastectomy desire immediate breast reconstruction. Postmastectomy radiation therapy (PMRT), however, increases the risk of surgical complications and may adversely affect the reconstructed breast. We compared outcomes of immediate latissimus dorsi myocutaneous flap (Lat Flap) versus tissue expander/implant (EI) reconstruction after mastectomy followed by PMRT in 29 women with invasive breast cancer treated at a single institution between 2009 and 2011. Although patients undergoing EI reconstruction were slightly younger and more frequently underwent bilateral mastectomy, there were no major differences between the groups with respect to patient or tumor characteristics. With a median follow-up of 11 months (Lat Flap) and 13 months (EI) after completion of PMRT, there was a trend toward more wound complications requiring reoperation, including expander/implant loss (n=3), in the EI group. Capsular contracture was the most common sequela of PMRT in the Lat Flap group (67%) but this was easily treated with capsulotomy at the time of nipple-areola reconstruction. Immediate breast reconstruction with a latissimus dorsi myocutaneous flap is a viable option for women undergoing mastectomy who are likely to require chest wall irradiation.