The aim of this study was to investigate the interrater reliability of the Revised Elderly Persons' Disability Scale (REPDS). In a correlational design four raters assessed 15 subjects all over the age of 65, and diagnosed as having dementia of varying stages of severity. All subjects attended day hospital facilities and were assessed by the raters. The raters comprised two staff nurses, one occupational therapist and one occupational therapy helper. Kendall's coefficient of concordance (W) was used to determine the overall interrater reliability of the REPDS as well as the seven subsections which make up this assessment tool. It was found that all of the subsections and the overall scale obtained significant values of W at the p < 0.05 level. The Spearman rank order correlation coefficient (rs) was used to compare the raters' scores individually, which suggested that the qualified members of the staff achieved slightly higher levels of interrater reliability in comparison to an unqualified staff member.