Background, A growing number of adult Americans are functionally illiterate. These people often do not understand educational documents written by health care professionals, especially if English is the reader's second language. This problem has received little attention in dentistry. Methods, In this study, the author selected a sampling of 24 patient educational documents from several dental resources and reviewed them for readability, using a computer-based program that assigns a reading level of understanding on the basis of a standard formula known as the Flesch-Kincaid Formula. The author also conducted a subjective review of each document to identify seemingly unnecessary professional jargon and words that were unlikely to be understood by many readers. Results, Reading levels varied from third to 23rd grade (according to the Flesch-Kincaid Formula), and 41.7 percent of the materials were written at greater than the recommended level for understanding by most patients (mean level: seventh to ninth grade). Many dental specialty publications were writ ten at or near college levels. Many documents had multiple grammatical errors. Seventy-nine words in the reviewed documents were considered to be jargon or potentially obscure to many lay readers. Conclusions, More attention needs to be focused on the preparation of written educational materials for dental patients, to make the documents more understandable to the average patient. Guidelines for acceptable writing are available in the medical, nursing and pharmaceutical literature.