The absence of progesterone receptor (PR) is attributable to low serum estrogen, low level of functional estrogen receptor (ER) nuclear and high expression of growth factors. Understanding the value of PR in human epidermal growth factor 2 (HER2) negative and ER positive breast cancer treat with tamoxifen (TAM) is important as TAM treatment is the main approach for ER+/HER2-breast cancer therapy. The aim of this study is to compare the efficacy of TAM treatment for PR+ and PR- breast cancer among ER+/HER2- cases. Clinical and follow-up data (the median follow-up time was 41 months) of 250 being ER+/HER2-breast cancer patients treated at Sichuan cancer hospital from 2005 to 2009 were collected, then the differences of overall survival (OS) and disease free survival (DFS) for PR+ and PR- cases with or without TAM therapy were analyzed by Kaplan-Meier and COX proportional hazards model. The results showed that the OS and DFS were similar between PR+ and PR- patients who without TAM treatment (P>0.05). Among patients who received TAM treatment, the 5-year OS were 91.2% and 68.2% in PR+ and PR- cases respectively (P=0.018) and the 5-year DFS were 81.2% and 63.1% respectively (P=0.030). PR-cases had higher risk for death, recurrence and metastasis (adjusted HROS=3.558, 95% CI: 1.061-11.932; adjusted HRDFS=2.498, 95% CI: 1.002-6.229) compared with PR+ cases. PR expression status significantly affected the efficacy of TAM endocrine treatment in ER+/HER2- breast cancer patients. PR-patients could get less benefit from the TAM treatment than PR+ patients.