Ideation activities take place in all parts of an organization and in different settings. Received theory points out that both formal and informal groups hold potential for creativity and knowledge creation, but how these groups differ in terms of ideation is not known. The importance of group heterogeneity and access to information and knowledge through network connections has been stressed in earlier research and the performed study has focused on these factors. More specifically, this research explores the ideation performance of project teams and informal groups, respectively, by studying how heterogeneity and network connectivity might influence the quality of the innovation ideas created. Drawing upon an internal database from a large Swedish consumer goods company, all innovation ideas created by both formal and informal group constellations during three years have been analyzed. The investigation showed that a moderate level of heterogeneity in formal groups has a positive influence on the quality of the ideas generated. The ideation performance of informal groups did not reveal any interdependence with heterogeneity. Network connectivity was interdependent with creative performance for informal groups, where a certain amount of connectivity positively influenced the performance of the group. The performance of formal groups did not show this pattern and also revealed no significant relationship with network connectivity. Based on the analysis, implications for management and theory are drawn and discussed.