Abstract: The objective of this study was to evaluate and document pain and psychological distress related to imaging-guided core needle biopsy (CNB) of the breast. This prospective study of 52 consecutive patients undergoing CNB of the breast assessed anxiety, pain, acute stress disorder, and activities of daily living both preprocedure and at 24 hours, 5 days, and 30 days postprocedure. Survey instruments included the State-Trait Anxiety Inventory (STAI), a visual analog pain scale, the SF-36 Physical Functioning Scale, and DSM IV criteria for acute stress disorder. Preprocedure the mean scores for self-reported levels of state and trait anxiety were 47.11 ( SD = 13.53) and 37.71 ( SD = 11.24), respectively. At 24 hours postprocedure, the mean score for self-reported state anxiety was 38.74 ( SD = 17.77), a significant reduction from the preprocedure level reported by patients (p < 0.005). Further reductions in state anxiety levels were reported at 5 and 30 days postprocedure. The mean scores for state anxiety fell within the normal range at 30 days postprocedure (mean 32.75, SD = 10.97). However, at 5 days post-CNB, patients with confirmed malignancies reported significantly more anxiety than patients without malignancies ( p = 0.002). This difference was not present at 30 days post-CNB ( p = 0.17). Patients reported average pain scores of 2.0 (on a scale of 0–10) during the biopsy. This decreased to 1.3 at 24 hours, 0.3 at 5 days, and 0.2 at 30 days. Reported symptoms of acute stress related to the procedure significantly increased over the period between the 5-day interview and the 30-day interview. One (2%) patient reported avoidance of thoughts about CNB 5 days postprocedure and 5 (12%) patients reported this at 30 days postprocedure (p < 0.05). Patients undergoing CNB reported significant levels of state anxiety which were greatest at the time of biopsy. A significant decrease was observed at 24 hours postprocedure, despite the fact that biopsy results were not available to the patients. Self-reported levels of anxiety for the group, regardless of biopsy results, fell within the normal range by 30 days. Further research and interventions are recommended to address the management of anxiety for patients undergoing CNB.