Objective: To investigate the clinicopathologic characteristics and prognostic factors of patients with stage IA breast cancer. Methods: The clinicopathologic data of 156 patients with IA stage (T1N0M0) breast cancer treated in Cancer Hospital of Tianjin Medical University from January 2004 to December 2009were retrospectively analyzed. Results: Of the 156 patients, all cases were female; infiltrate ductal carcinoma accounted for the majority of the pathological types (115 cases, 73.7%), the primary tumor sizes were mostly classified as T1c (77 cases, 49.4%) and histological grades were mainly grade II (79 cases, 50.6%) and III (58 cases, 37.2%). The 5-year progress-free survival (PFS) was 93.3% and overall survival (OS) was 99.1%, respectively. Univariate analysis showed that histological grade, Ki-67 expression and lymphvascular invasion were significantly related to the PFS of the patients (all P<0.05). Multivariate analysis identified that histological grade and Ki-67 expression were independent prognostic factors for PFS of the patients (both P<0.05). Conclusion: Although the overall prognosis of stage IA breast cancer patients is favorable, patients in some subgroups still have great risk of recurrence and metastases, and they have a poor prognosis.