Background: Skin biopsy specimens are submitted for “rush” or “stat” processing, thereby indicating a sense of urgency about the clinical situation. Objective: Our purpose was to determine the patient population who underwent biopsy on a “rush” basis and assess the way in which interpretation of the skin biopsy specimen influences clinical management. Methods: A retrospective study was performed on the “rush” biopsy specimens sequentially requested during 1 year. Histologic findings, the clinical situation, and the effect of the biopsy result on clinical management were determined. Results: A total of 90 adult patients, many critically ill, were identified. The majority of patients were admitted to hematology-oncology services (58%). The other 42% were admitted to a variety of clinical services. The chief clinical concerns in hematology-oncology patients were graft-versus-host disease and cutaneous infection. Only 5.5% of biopsy specimens taken to exclude graft-versus-host disease were used in immediate clinical decision-making compared with 45% of biopsy specimens for oncology patients with suspected infection and 42% for all other services. Conclusion: Many urgent skin biopsy specimens were not used for immediate clinical decision-making. The usefulness of skin biopsy varies with the clinical situation, and some situations are more prone to yield equivocal histologic data. Knowledge of these situations may reduce the number of unhelpful biopsy specimens. Therapy based on clinical findings had often been initiated before receiving the biopsy results, but biopsy findings are often helpful as confirmatory data. Diagnostic findings were not necessary for a biopsy specimen to provide useful data and nonspecific findings interpreted in light of clinical findings were also useful. (J Am Acad Dermatol 1998;38:548-54.)