The Cardiotoxicity of Chemotherapy Knowledgebase (CATCH-KB) contains information extracted from articles investigating an association between germline genetic polymorphisms and the development of chemotherapy-induced cardiotoxicity (CIC) in cancer patients receiving antineoplastic treatments. CATCH-KB also contains integrated gene and drug information from open biomedical resources such as PharmGKB1 and SIDER2. Furthermore, the genetic polymorphisms, drugs, and cancer types detailed in CATCH-KB are standardized according to appropriate biomedical ontologies, such as SNOMED-CT3 and RxNorm4. CATCH-KB currently contains information on 49 research papers published between 2004 and 2017 investigating a total of 2,210 variants in over 280 genes for an association with CIC. By centralizing this information and linking it to external open-access biomedical resources, CATCH-KB will facilitate hypothesis generation and meta-analysis efforts and will ultimately accelerate the use of genetic screening in preventing CIC. CATCH-KB is publicly accessible via http://catchkb.org.