The College of American Pathologists Interlaboratory Comparison Program in Non-Gynecologic Cytopathology is a popular educational program for nongynecologic cytology, with 1018 participating laboratories by the end of 2000. Data generated from this program allow tracking pathologist performance in a wide variety of laboratory practices. To review performance of participating pathologists in making patient diagnoses with fine-needle aspiration biopsy specimens, with particular interest in the false neoplastic diagnoses (both benign and malignant neoplasms) that were submitted for benign aspirates containing only normal cellular components. We reviewed the diagnoses made from 1998 through 2000 by participating pathologists through the use of glass slides containing benign fine-needle aspiration biopsy specimens of the liver, kidney, pancreas, and salivary gland that contained only normal cellular components. The false neoplastic rate for kidney (60%) was the highest, followed by liver (37%), pancreas (10%), and salivary gland (6%). These rates are much higher than what has previously been reported in the literature. This study illustrates that normal cellular elements are a significant pitfall for overinterpretation of fine-needle aspiration biopsy specimens.