The purpose of the study is to develop and validate the Work Addiction Inventory (WAI). The WAI is designed to assess individual's addiction to work via self-report. Data were collected from 127 working professional employed on at least a part-time (20 hours per week) basis. Results of an exploratory factor analysis retained 24 items and indicated that the WAI consists of three underlying factors. The WAI subscale and total scores showed adequate internal consistency reliabilities. Convergent and discriminant validity was initially supported by the relationship between WAI scores, an existing measure of workaholism, and social desirability. Also, WAI scores correlated highly with several criterion variables. Finally, evidence was found to suggest that the WAI accounts for unique variance beyond an existing measure of workaholism. In conclusion, psychometric properties of the WAI were initially supported by findings of the study.