['Touch preparation cytology (TPC) has proven to be a quick and accurate intraoperative diagnostic tool for excisional breast biopsy, margins and sentinel nodes. We hypothesized that TPC of core needle biopsy (CNB) specimens can provide a same-day diagnosis in the outpatient setting.', 'Outpatients presenting with breast lesions underwent TPC of biopsy cores performed by biopsy gun or vacuum-assisted CNB. The TPC results were compared with the final diagnosis of CNB specimens.', 'In all, 199 CNB and TP were performed between August 1997 and October 2002. Twenty-nine percent of lesions were malignant. Touch preparation was deferred in 21% of cases. In the remaining 157 evaluable cases, TPC had an accuracy of 89% and a false negative rate of 26%. The sensitivity, specificity, positive predictive value and negative predictive value of TPC were 74%, 97%, 93%, and 86% respectively.'] Is touch preparation of breast core needle specimens a new method for same-day diagnosis?