Interpersonal trust and group trust are factors which are critical to the success and cohesion of virtual communities. One such type of virtual community is the Open Source Application Development community. This study examines the influence of cognitive trust and affective trust in a large, active virtual community (SourceForge.Net) involved in open source application development. We find that cognitive and affective trust are both related to group cohesion and project outcomes in free/open source projects, as well as the perceived benefits group members derive from membership. Cognitive trust shows a more significant relationship to project outcomes while affective trust is more significantly related to group cohesion and perceived benefit.