This paper explores the role of migrant networks in international migration from a comparative perspective by analysing networks in two different migratory settings. We compare life course data on first migration using two comparable datasets: the Mexican Migration Project (MMP 2000-2012) and the Migrations Between Africa and Europe survey (MAFE 2008-11). We apply strictly equivalent definitions and methods, allowing us an assessment of the role of networks in international migration. Our general hypothesis is that networks become more important in migration flows and periods where difficulties and costs of migration are higher. We focus on the resources conveyed by networks, on the stage of the migratory system, and on gender differentials. Using event-history analysis, first preliminary results indicate that close migrant networks (parents and siblings) are strong predictors for an individual’s first migration in both migratory systems. For men, close networks have a similar impact in both migration flows. For women, however, the effect appears to be larger for Mexican migrants to the US, compared to the Senegalese. The study is relevant to the field of migration research both from a substantial and a methodological point of view. Firstly, substantively, we expect to contribute to the literature on networks in the context of international migration by putting the existing theoretical approaches and empirical findings on migration networks in an international comparative perspective. Secondly, the paper is also relevant from a methodological point of view, since it is the first comparison of two different migration flows examining the impact of networks on migration probabilities at the individual level, using the same methodology and definitions.