This Practice Note looks at which Croatian nationals are required to obtain authorisation to work in the UK under the Accession of Croatia (Immigration and Worker Authorisation) Regulations 2013 and the relevant application procedure that will apply. Work authorisation covers the following categories: Tier 2 (General), Tier 2 (Intra-Company Transfer), Tier 2 (Minister of Religion), Tier 5 (Temporary worker): Religious Workers, Tier 5 (Temporary worker): Government Authorised Exchange, Tier 5 (Temporary worker): International Agreement, Tier 5 (Temporary worker): Charity Workers, Postgraduate doctors and dentists, Domestic workers in a private household and Representative of an Overseas Business.