This paper provides the first direct evidence on the determinants of link formation among immigrants in the host society. We use a purposely-designed survey on a representative sample of Sri Lankan immigrants living in Milan to study how migrants form social links among them and the extent to which this network provides them with material support along three different dimensions: accommodation, credit, job-finding. Our results show that both weak and strong ties are more likely to exist between immigrants who are born in close-by localities at origin. The time of arrival has a U-shaped effect: links are more frequent between immigrants arrived at the same time, and between long-established immigrants and newcomers. Once the link is formed, material support is provided mainly to relatives while early migrant fellows are helpful for job finding.