This paper analyses whether international migrants contribute to foster innovation in developing countries by inducing a transfer of productive knowledge from destination to the migrants’ home countries. Using the Economic Complexity Index as a proxy for the amount of productive knowledge embedded in each countries, and bilateral migrant stocks to 20 OECD destination countries, we show that international emigration is a strong channel of technological transmission. Diasporas foster the local adoption of new technologies by connecting high technology countries with low ones, reducing the uncertainty surrounding their profitability. Our empirical results support the fact that technological transfers are more likely to occur out of more technologically advanced destinations and when emigration rates particularly high.