Past studies loosely define culturally heterogeneous group composition as any combination of mixed nationality and/or ethnicity. A case study with three project groups was conducted to investigate if culturally diverse groups composed differently in terms of nationality/ ethnicity mix will experience different types of communication problems. Communication problems of discussion dominance, reduced communication frequency and discussion exclusion were coded from taped discussions. Findings indicate that ethnicity and nationality give rise to different communication problems. Future studies should be specific when defining heterogeneous groups in terms of whether they are manipulating differences in nationality, ethnicity or both.