Pseudoalteromonas　sp.　CuT4–3,　a　copper　resistant　bacterium,　was　isolated　from　deep-sea　hydrothermal　sulfides　on　the　Southwest　Indian　Ridge　(SWIR),　is　an　aerobic,　mesophilic　and　rod-shaped　bacterium　belonging　to　the　family　Pseudoalteromonadaceae　(class　Gammaproteobacteria,　order　Alteromonadales).　In　this　study,　we　present　the　complete　genome　sequence　of　strain　CuT4–3,　which　consists　of　a　single　circular　chromosome　comprising　3,660,538　nucleotides　with　41.05%　G　+　C　content　and　two　circular　plasmids　comprising　792,064　nucleotides　with　40.36%　G　+　C　content　and　65,436　nucleotides　with　41.50%　G　+　C　content.　In　total,　4078　protein　coding　genes,　105　tRNA　genes,　and　25　rRNA　genes　were　obtained.　Genomic　analysis　of　strain　CuT4–3　identified　numerous　genes　related　to　heavy　metal　resistance　(especially　copper)　and　EPS　production.　The　genome　of　strain　CuT4–3　will　be　helpful　for　further　understanding　of　its　adaptive　strategies,　particularly　its　ability　to　resist　heavy　metal,　in　the　deep-sea　hydrothermal　vent　environment.　©　2024　Elsevier　B.V.