It has become increasingly apparent that cytotoxic drugs given systemically for non-CNS tumours might have cognitive side-effects, but many fundamental questions require further elucidation, and large samples from several institutions are needed. Two working groups brought together by the International Cognition and Cancer Task Force (ICCTF) developed recommendations for a core set of neuropsychological tests, common criterion for defining cognitive impairment and cognitive changes, and common approaches to improve the homogeneity of study methods. These recommendations will improve research design and facilitate study combinations, between-study comparisons, and meta-analyses, which will allow more accurate estimates of incidence, severity, individual risk factors, and causes of cognitive problems associated with chemotherapy for non-CNS tumours. Copyright © 2011 Elsevier Ltd. All rights reserved.