Transnational perspectives on migration have challenged conventional understandings of migrant assimilation. However, theories on the relation between transnational engagement and integration are still offering a quite dualistic picture. Until today, few quantitative studies have been conducted on the consequences of transnational activities for immigrant integration, especially within the European context. The objective of this study is to provide empirical knowledge that enables a further evaluation of the accuracy of classic assimilation theory in a society where a growing part of the population is believed to maintain cross-national ties. With the use of data from The Swedish Level of Living Survey of Foreign Born (LNU-UFB) the study focuses on three different aspects of integration outcomes: social, cultural and economic integration. The study finds significant correlations between transnational activities and all three integration outcomes, also when well-known determinants of integration are controlled for. The directions of these associations are similar across each aspect of integration but vary with type of transnational activity. Whilst sending remittances and travelling frequently to the country of origin are positively associated with social, cultural and economic aspects of integration, longer duration of stay in the country of origin is negatively associated with integration outcomes. Both number and length of visits are additionally found to be more important for migrants who have recently come to Sweden and were older when migrating than those having lived in Sweden a longer period of time or from young ages.  Noting the underlying and multi-directional causality, the results overall imply a further critique of the classic assimilationist view, supporting a more pragmatic view of both integration and transnational activities as parts of the same processes.