Our understanding of the biology of cancer and the application of this knowledge to cancer treatment has greatly outpaced what we know of the biology underlying the symptoms and toxic effects that therapies produce. These adverse effects of therapy cause substantial discomfort and distress to patients and their families, limit treatment tolerability and can persist indefinitely in post-treatment survivorship. Despite these concerns, little research effort is targeted at documenting the nature of these effects. Similarly, limited efforts are being made in the drug-development arena to identify or develop treatments that might prevent or reduce toxicities. A panel of clinicians and researchers as well as representatives from advocacy groups, federal agencies and the pharmaceutical industry was convened to identify gaps in cancer treatment toxicity research and to provide direction for future action. With an emphasis on coordinating multidisciplinary efforts, this panel has presented a strategy to increase funding for the field and develop a coherent research agenda.