The present study sought to empirically identify what factors are important for international assignee perceived success along with their relative importance. Subjects were 338 international assignees from diverse countries (nationality) and organizations, assigned to diverse countries, and performing diverse jobs. Five factors were identified and in a descending order of importance, these were Family Situation, Flexibility/Adaptability, Job Knowledge and Motivation, Relational Skills, and Extra-Cultural Openness. Although importance ratings were not influenced by job type (managerial/nonmanagerial status), they were influenced by organizational type. In general, the pattern of importance ratings for service organization international assignees was different from those of international assignees from other organizational types. Furthermore, service organization international assignees ascribed more importance to relational and psycho-social factors. The perceived relative importance of psycho-social factors reported by the study's participants tends to suggest that more attention should be paid to these factors in the selection and training of international assignees.