Understanding of the effectiveness of work-teams is a major issue in the business world, where they are expected to facilitate developing individual skills and increasing organizations’ efficiency. Eighty-three engineers working in teams have responded to a questionnaire devised to measure perceptual power distances, the sense of relatedness, cohesion measured by integration around the task, and teams’ effectiveness. Results reveal that “task cohesion” and sense of relatedness mediate the relationship between power distance and perceived effectiveness. These results are related with those observed in the context of the self-determination theory and presented in order to highlight their practical implications.