This article describes preliminary diagnostic validation of scores from the Hurvich Experience Inventory/50 (HEI/50), which was developed to measure individual variation in the frequency of consciously acknowledged annihilation anxiety in adults and adolescents and to predict the need for psychiatric services. Analyses of the responses of 1,246 university students, community adults, and clinic clients showed that the HEI/50 anxiety total (A) and critical 12 high (C12high) scores were associated with various clinical indices, and that the C12high score exhibited diagnostic utility equivalent to the State-Trait Anxiety Inventory (STAI), Beck Depression Inventory-IA (BDI), and Symptom Checklist-90-R (SCL-90R) for predicting clinical status. Sequential multiple regression analysis suggested that the HEI/50 A score predicts unique variance in overall psychological distress, and is better than the BDI and STAI for predicting such distress. The usefulness of the HEI/50 in assessing annihilation anxieties in students and future research directions is suggested.