This study was conducted to assess the readability and length of informed consent documents used in clinical trials in oncology. One hundred seven consent documents from clinical protocols open to accrual at the Emory University Winship Cancer Institute were quantitatively analyzed. These included trials sponsored or organized internally, by commercial interests, and by various cooperative groups. Each form was analyzed using the electronic text version of the consent document approved by the Emory University IRB. Readability software was used to determine the length of each document and 2 measures of readability: The Flesch Reading Ease Score and a grade-level readability estimate using the Gunning Fog Index. The mean length +/- SD was 2709 +/- 971 words or 10.8 +/- 3.8 pages. The mean +/- SD Flesch Reading Ease Score was 45.48 +/- 5.24. The mean +/- SD grade level using the Gunning Fog Index was 11.9 +/- 1.53. None of the consent documents were written at or below the 8th-grade reading level; 1.8% were at or below the 9th-grade level; 10.5% were below the 10th-grade level. Results were similar regardless of study sponsor. Consent documents for clinical trials in oncology are lengthy and complex to the point that is unlikely that most patients will be willing to read them or be able to understand the concepts they discuss. IRBs and cooperative group review committees are either unwilling or unable to enforce widely accepted readability standards for the consent document. We discuss the implications of this situation and suggest ways to improve it.