The last decade has witnessed increasing interest in email communication. Research in this area has focused on stylistic conventions, the role of email in the communication patterns of a company and the link between emails and corporate culture. Most of the studies so far published have concentrated on simple, one-way emails. However, evidence from a databank of 123 emails for international business communication seems to suggest that emails are gradually becoming a more complex genre. This article analyses the emerging textual and communicative complexity of business emails from the databank and suggests that this complexity has resulted mainly from efforts to accommodate the genre to the new demands of the international business community.