A Practice Note analyzing the key US federal laws governing cross-border service of process. This Note discusses serving process under an international treaty, including the 1965 Convention on the Service Abroad of Judicial and Extrajudicial Documents in Civil or Commercial Matters (Hague Service Convention or HCCH 1965 Service Convention) and the Inter-American Convention on Letters Rogatory, serving process under FRCP 4(f)(2) and 4(f)(3), and related issues such as proof of service and timing of service. This Note also discusses serving foreign individuals and entities within the US, serving foreign sovereigns under the Foreign Sovereign Immunities Act (FSIA), and cross-border service in cases pending in state court.