[en] The mechanisms of exogamy and endogamy among immigrants are considered important indicators of social integration in the host society. The goal of this paper is to analyze the patterns of union formation among ex-Yugoslav of the first and second generation in Sweden. The study analyzes both marriages and non-marital childbearing unions. The longitudinal data (1990-2012) stem from the STAR compilation of the Swedish register data. The data cover the entire population residing in Sweden. The main analysis is based on discrete-time multinomial logistic regression. The results show that the length of stay in Sweden is positively associated with the likelihood of a union with a native Swedish person and negatively associated with the likelihood of an endogamous partner choice. A stronger exposure to ex-Yugoslav immigrants (measured as the share of ex-Yugoslavs in the municipality) implies a higher likelihood of endogamous union and a lower likelihood of a union with a native. University educated ex-Yugoslavs are the most likely to enter a union with a native, with the association being more pronounced among women. The patterns of intermarriage among ex-Yugoslavs largely resemble those identified in previous studies on native-immigrants marriages in Europe. One exception is that the propensity for endogamy is somewhat more pronounced among women. In order to obtain a more fine-grained picture of the causal mechanisms behind the results reported in this study, it will be necessary to conduct additional research, combining quantitative and qualitative methods.