The aim of this study is to examine the differences between native Swedish and immigrant entrepreneurs' business networks at start-up stage. The study is based on a database consisting of 261 immigrant- and 2,463 native-owned companies, applying several univariate and multivariate statistical methods. Immigrant entrepreneurs' business networks are less likely to include mainstream contacts at the start-up stage than native born entrepreneurs. Thus, ethnicity is an important variable explaining differences in such networks at the start-up stage. A combination of both mainstream and immigrant networks has the potential to give rise to more growth for immigrant-owned businesses. As a result, these businesses may have potential to create new jobs for unemployed immigrants. This study provides a deeper understanding of how ethnicity may influence the entrepreneurs' use of business networks. It may lead to policy makers considering access to mainstreaming networks as an important issue in the social and economic integration.