NIF — Número de Identificação Fiscal

The NIF (Número de Identificação Fiscal) is the 9-digit Portuguese tax identification number issued by AT. It is required for virtually all financial and legal transactions in Portugal: opening a bank account, signing a rental contract, purchasing property, filing an IRS return, receiving income, and applying for special tax regimes. EU/EEA citizens can obtain a NIF at any AT office (Finanças) with a passport or national ID. Non-EU citizens typically need a fiscal representative to obtain a NIF before establishing residency. Once tax residency is established, the NIF is linked to the taxpayer's Portuguese tax record. The NIF is different from the Número de Segurança Social (social security number, NISS) and the Número de Identificação Civil (citizen ID number).