The proposition that firm size is positively associated with certain aspects of export behavior is often taken for granted. However, results from past literature do not definitively support this proposition. The research presented here attempts to re-clarify these conflicting findings in the export marketing literature by empirically examining the impact of firm size on two aspects of export behavior, one relating to export performance and the other concerning company's attitudes toward export. This study is based on responses to questionnaires by 86managers of Thai exporting firms. The results indicate that exporting firms of different sizes did, to a certain degree, differ significantly in many of the export performance and attitudes variables being studied;but larger exporting firms did not necessarily perform better than smller exporting firms, nor did they have more positive attitudes toward export.