The present invention discloses antibodies which bind human andMacaca fascicularisCEACAM5 proteins, as well as isolated nucleic acids, vectors and host cells comprising a sequence encoding said antibodies. The invention also disclosess immunoconjugates comprising said antibodies conjugated or linked to a growth-inhibitory agent, and to pharmaceutical compositions comprising antibodies, or immunoconjugates of the invention. The antibodies or immunoconjugates of the invention are used for the treatment of cancer or for diagnostic purposes.本發明揭示結合人類及食蟹獼猴(Macaca fascicularis) CEACAM5蛋白之抗體以及包括編碼該等抗體之序列之經分離核酸、載體及宿主細胞。本發明亦揭示包括該等抗體偶聯或連接至生長抑制劑之免疫偶聯物,及包括本發明抗體或免疫偶聯物之醫藥組合物。本發明之該等抗體或免疫偶聯物係用於治療癌症或用於診斷目的。