The purposes of this study were to compare test-retest reliability of measurements obtained by the use of a photographic method and those obtained by the use of a transparency method and to compare wound surface area (WSA) measurements obtained by these two methods. Twenty inpatients (18 male, 2 female), aged 31 +/- 16 years (mean +/- SD), participated in the study. Tracings of ulcer borders generated by the photographic and transparency methods were digitized to obtain WSA measurements. To assess intrarater reliability for each method, 5 ulcers were measured on two occasions. The magnitude of WSA measurements obtained by the photographic and transparency methods was compared in 22 ulcers measured on one occasion and in 16 ulcers measured at 5-day intervals for 20 days. Intraclass correlation coefficients (ICCs) were high (ICC = .99) for each method, indicating reliability of measurements. The WSA measurements did not differ between photographic and transparency methods, either at one occasion or over a 20-day period. We concluded that the photographic and transparency methods, as applied in this study of ulcers, provided equivalently reliable measurements and that WSA measurements obtained by the two methods were equivalent. The transparency method was more economical than the photographic method in terms of time and equipment requirements.