Background: Whether sentinel lymph node biopsy (SLNB) should be performed in patients with pure ductal carcinoma in situ (DCIS) of the breast has been a question of debate over the last decade. The aim of this study was to identify factors associated with microinvasive disease and determine the criteria for performing SLNB in patients with DCIS. Materials and Methods: 125 patients with DCIS who underwent surgery between January 2000 and December 2008 were reviewed to identify factors associated with DCIS and DCIS with microinvasion (DCISM). Results: 88 patients (70.4%) had pure DCIS and 37 (29.6%) had DCISM. Among 33 DCIS patients who underwent SLNB, one patient (3.3%) was found to have isolated tumor cells in her biopsy, whereas 1 of 14 (37.8%) patients with DCISM had micrometastasis (7.1%). Similarly, of 16 patients (18.2%) with pure DCIS and axillary lymph node dissection (ALND) without SLNB, none had lymph node metastasis. Furthermore, of 20 patients with DCISM and ALND, only one (5%) had metastasis. In multivariate analysis, the presence of comedo necrosis [relative risk (RR)=4.1, 95% confidence interval (CI)=1.6-10.6, P=0.004], and hormone receptor (ER or PR) negativity (RR=4.0, 95%CI=1.5-11, P=0.007), were found to be significantly associated with microinvasion. Conclusions: Our findings suggest patients presenting with a preoperative diagnosis of DCIS associated with comedo necrosis or hormone receptor negativity are more likely to have a microinvasive component in definitive pathology following surgery, and should be considered for SLNB procedure along with patients who will undergo mastectomy due to DCIS.