Background: Receptor status is a determinant of breast cancer (BC) treatment and prognosis. Clinical practice guidelines advise that all women diagnosed with BC may undergo estrogen (ER), progesterone (ER) and human epidermal growth factor 2 (HER2) receptor tests. We conducted a population-based study to investigate what proportions of women undergo testing and predictors of test receipt. Methods: Incident BCs (ICD10 C50) diagnosed 2006-2008 were identified from the National Cancer Registry Ireland. Receptor tests were identified from registration records augmented by review of selected medical records. For each of the three receptors separately, logistic regression was used to identify which socio-demographic (age, marital status, smoking status, area of residence, and deprivation category) and clinical factors (grade, tumour size (T), nodal status (N), distant metastasis (M)) were associated with undergoing testing. Adjusted odds ratios (OR) and 95% confidence intervals were computed. Results: 7619 BCs were included. 7% were not tested for any of the receptors. 73% were tested for all three. Considering each receptor separately, 90% had an ER test, 86% a HER2 test and 80% a PR test. Women with T4 tumours were less likely to have ER and HER2 tests, and more likely to have a PR test, than women with T1 tumours. After adjustment for clinical variables, age was not a significant predictor for ER and HER2 testing, while older women (≥70) were more likely than younger women to have a PR test. For all three tests, non-married women were significantly less likely to be tested (ER: OR=0.65, 95%CI 0.52-0.8; PR: OR=0.81, 95%CI 0.7-,0.93; HER2: OR=0.72, 95%CI 0.62-0.85) and current smokers more likely (ER: OR=1.55, 95%CI 1.14-2.1: PR: OR=1.38, 95%CI 1.15-1.66; HER2: OR=1.25, 95%CI 1.01-1.55). Area of residence at diagnosis was a significant predictor of having each test, although the geographical patterns varied. Conclusions: More than one-quarter of women with BC do not have one or more of the receptor tests. After adjusting for clinical variables, socio-demographic factors were significant predictors of test receipt. In the interests of equity, the reasons underlying these associations should be further investigated.