This Master's Project is carried out in the context of the NECA project. The NECA project develops a system that generates multi-modal dialogues for embodied conversational agents. The aim of this project is to develop and implement an algorithm that generates feedback gestures for the characters in the dialogue. Subsequently the effects feedback gestures might have on the general impression of the dialogue are evaluated. Feedback gestures are performed by a person involved in a conversation but not having the speaking turn at the moment. This person supplies the speaker with feedback so that the speaker knows if s/he has understood or not. The effects were measured in terms of entertainment, naturalness, liveliness and ability to remember the dialogue content. The algorithm was developed and implemented and an evaluation was carried out. The evaluation results show no big differences in the subjects' apprehension of the dialogue with feedback gestures compared to the dialogue without feedback gestures. The subjects judged the dialogue without feedback gestures as slightly more entertaining and natural but the one with feedback gestures was judged as livelier. The memory test shows that the subjects remembered the content of the dialogue without feedback gestures better than the content of the dialogue with feedback gestures.