This study explores the technical viability of autologous fat grafting for immediate partial breast reconstruction following the primary conservative surgery for breast cancer; restoring volume, shape, and symmetry to the treated breast. We analyze the impact in relation to mammographic follow-up and the subjective degree of satisfaction with esthetic results and although we didn't have any local failure during the observation period; we understand that is too early for any kind of conclusion. From June of 2010 to July of 2011, 20 patients were selected for breast-conserving surgery (BCS) with partial breast reconstruction with autologous fat grafting performed during the same operation by the same medical team. The fat graft was injected in the subcutaneous and intraglandular breast tissue around the resected area. We performed an overcorrection, predicting a resorbing of about 30–50% of the volume grafted. All patients received the literature-based recommendations for breast cancer treatment with complementary radiotherapy. The follow-up period after the completion of radiotherapy ranged from 13 to 29 months. The average volume grafted was 121 cc and it was 2.1 times larger than the resected volume. The esthetic scores were considered very good or good in the majority of cases. Mammograms were taken every 6 months after radiotherapy and only one patient had a mammogram classified as BI-RADS 3, suggesting fat necrosis. The remaining patients were classified as BI-RADS 2. Immediate autologous fat grafting is a promising technique for partial breast reconstruction after BCS. It is associated with high patient and physician satisfaction. It is an alternative for reconstruction of small- and medium-sized breasts. This technique has the advantage that enables the reconstruction of defects in areas difficult to repair, particularly in the upper inner quadrants. It also may reduce the need for major glandular or myocutaneous flaps mobilization.