There is ample empirical evidence for the impact of gender in face-to-face negotiations. In electronic negotiations, the use of electronic negotiation support systems (eNS) implies important differences to face-to-face communication settings: (1) eNSs permit among other functions, revising, storing, processing, and transmitting information and (2) Computer-mediated communication reduces the transmission of interpersonal and social context cues. In this study, we use a controlled laboratory experiment to analyse how the negotiators' gender, the gender-composition of negotiation dyads as well as the negotiators' prior relationship affect negotiation behaviour in electronic negotiations. Our results clearly indicate stereotypical behaviour of men and women in electronic negotiations: Overall, women give more information about their personal interests and needs and tend to be more yielding while men, on the contrary, tend to be more persuasive and competitive. When negotiating with a friend, men show significantly more integrative negotiation behaviour while women's behaviour does not change to a great extent. Finally, we find the gender-specific adaptation of negotiators to their counterpart to be relatively low indicating less gender salience in electronic negotiations.