The quality of reported research representing a number of disciplines involved in diabetes patient education was investigated in this study. A rigorous literature search identified 47 studies reported between 1954 and 1986 that met inclusion criteria; 29 were published studies, 18 were unpublished. Quality of the research was measured by Duffy's Research Appraisal Checklist (RAC) and also by coding each study as to the number of threats to internal and external validity present. Overall quality as measured by the RAC ranged from 34 to 95 on a 100-point scale. A statistically significant relationship was found between publication date of the research report and quality, indicating improvement in quality during recent years. Quality of published versus unpublished research reports was not found to differ significantly. Recommendations for improving methodological rigor of future studies include: (a) the use of more rigorous designs, particularly those involving control groups such as randomized clinical trials; (b) reporting of more complete data in research reports; and (c) monitoring of the quality of future studies.