Metallodrugs　are　important　for　anticancer　treatments.　They　bind　mainly　to　human　serum　albumin　(HSA)　in　blood　circulation,　greatly　modulating　their　pharmacokinetics　and　anticancer　efficacy.　Fatty　acid　(FA)　is　one　of　the　most　important　endogenous　ligands　of　HSA　with　tight　binding　to　HSA　and　affecting　its　conformation.　However,　the　effect　of　fatty　acids　on　metallodrugs　interaction　with　HSA　is　unknown.　Here　we　identify　the　binding　sites　of　a　widely　used　metallodrug,　cisplatin,　in　HSA　in　the　presence　or　absence　of　a　representative　fatty　acid,　myristate,　by　X-ray　crystallography.　Our　crystal　structures　indicate　that　the　sidechain　of　residue　Met548　becomes　more　exposed　to　solvent　in　the　presence　of　fatty　acid,　and　is　the　main　Pt　binding　site　together　with　Met329　in　HSA:Myr:cisplatin　ternary　structure.　An　undoubted　new　Pt　binding　site　is　detected　at　His338　in　the　presence　of　fatty　acid,　and　additional　two　sites　are　also　identified　at　His146　and　His440　+　K436.　In　addition,　we　revealed　the　mechanism　of　cisplatin-induced　HSA　aggregation,　which　is　due　to　the　crosslinking　between　Met298　and　His510　of　two　HSA　molecules.　©　2022