Decreased or absent progesterone receptor expression in invasive breast carcinoma is a marker for an adverse prognosis. As part of an ongoing quality assurance study, this study evaluated the relationship between Oncotype DX recurrence score and progesterone receptor immunohistochemical result within each Nottingham tumor grade in 1074 cases of invasive breast carcinoma for which an Oncotype DX recurrence score was available. In addition to a statistically significant association between Nottingham grade and Oncotype DX recurrence score categories (P < 0.001), an inverse relationship was identified between progesterone receptor expression measured by modified H-score semiquantitation and Oncotype DX recurrence score that was independent of Nottingham tumor grade. The Oncotype DX recurrence score relies heavily on parameters already available from routine pathologic examination, and consideration of progesterone receptor status may aid in selection of patients most likely to benefit from ancillary testing.