The Social Phobia Inventory (SPIN) is a new self-rated scale designed to assess the full spectrum of fear, avoidance, and physiological symptoms associated with social phobia. The study aimed to validate the SPIN's psychometric properties. The SPIN consists of 17 items rated on a scale from 0 to 4, covering fear of social situations, avoidance behaviors, and physiological discomfort. The scale was administered to subjects from three clinical trials and two control groups. Results showed good test-retest reliability, internal consistency, and convergent and divergent validity. A SPIN score of 19 distinguished between social phobia subjects and controls. The SPIN was responsive to changes in symptoms over time and reflected different responses to active drugs versus placebo. Factorial analysis identified five factors, reflecting different aspects of social phobia. The SPIN demonstrates solid psychometric properties and shows promise as a screening tool and measure of treatment response in social phobia. However, further studies are needed to validate its use in different populations, including children, ethnic minorities, and non-English speakers.The Social Phobia Inventory (SPIN) is a new self-rated scale designed to assess the full spectrum of fear, avoidance, and physiological symptoms associated with social phobia. The study aimed to validate the SPIN's psychometric properties. The SPIN consists of 17 items rated on a scale from 0 to 4, covering fear of social situations, avoidance behaviors, and physiological discomfort. The scale was administered to subjects from three clinical trials and two control groups. Results showed good test-retest reliability, internal consistency, and convergent and divergent validity. A SPIN score of 19 distinguished between social phobia subjects and controls. The SPIN was responsive to changes in symptoms over time and reflected different responses to active drugs versus placebo. Factorial analysis identified five factors, reflecting different aspects of social phobia. The SPIN demonstrates solid psychometric properties and shows promise as a screening tool and measure of treatment response in social phobia. However, further studies are needed to validate its use in different populations, including children, ethnic minorities, and non-English speakers.