Latex allergy is a known cause of allergic contact dermatitis. It produces mild symptoms, including skin rash and itching, which usually subside in a few days. However, latex allergy can also induce anaphylaxis, a severe type I hypersensitivity reaction that can cause urticaria, angioedema, hypotension, tachycardia, and bronchospasm. We report a case of anaphylactic shock during gastric cancer surgery in a patient with no previous allergic history. Surgery was suspended when hypotension, tachycardia, and wheezing developed. A thorough workup revealed that the patient had a latex allergy. The patient subsequently underwent curative gastrectomy performed with latex-free procedures.