Introduction: Accurate wound size measurement is vital to assessment of progressive healing. Lack of an accepted “gold standard” is a major obstacle to assessment of any effective wound management regimen. Methodology: Sixteen pelvic region pressure ulcers were monitored weekly for 3 weeks. All wounds were stage III or IV, equally divided between sacral and ischial locations. Linear wound size was measured using the Decubitus Disposable Measuring Guide (DDMG). Wound size index was defined as the sum of the linear dimensions. Wound volume was determined by filling the covered wound cavity with fluid; the volume of saline required to fill the wound was a direct measure of wound volume. Results and Discussion: Correlation between the two measurement methods was determined utilizing Spearman’s rank correlation coefficient. Wound size index decreased significantly (p < 0.01) over the study period. Wound volume changes were nonsignificant. Closer evaluation of assessment methodology found missing wound volume data, due primarily to patient positioning difficulties. All missing data points were for ischial wounds. Wound absorption of measurement fluid and residual fluid in the wound prior to measurement could not be determined. Wound size index may be influenced by subjective evaluation of wound boundaries. Conclusion: Wound size index significantly discriminated longitudinal changes in wound size, while volume measurements did not. Wound volume measurements have greater measurement errors than wound size index. Acknowledgments: Support for this study was provided by the Veterans Administration Rehabilitation Research and Development Service.