Background: Lymphedema is a common complication following breast cancer treatment, estimated to affect 20% of breast cancer survivors. The condition is associated with a number of symptoms, such as impaired range of motion and anxiety. A wide range of methods for determining the volume of the lymphedematous arm have been described. Circumference measurement (CM) is commonly used in clinics to appraise arm volume, while water displacement (WD) is often used in studies. The aim of the study was to assess the performance of a new method using 3D-technology in comparison to CM and WD. Methods and Results: The study was performed on 25 subjects with lymphedema secondary to breast cancer treatment. Volumetric data from CM, WD, and the 3D-camera were gathered on all subjects. The measurements were performed by two physiotherapists, each subject being measured by one of the physiotherapist. Estimates of differences between the methods was calculated through analyzing the data collected from the three methods using mixed-design analyses of variance. The results indicated a tendency for the 3D-camera to overestimate the volume in comparison the WD by 45.25 mL, 95% confidence interval (CI) -36.31 - 126.82 (p value 0.270). Conversely, CM showed a tendency to underestimate the volume compared to WD (-24.28 mL, CI -99.78 - 51.22, p value 0.521). Thus, no statistically significant difference was found between the methods. Conclusions: The 3D-camera is a viable method for measuring arm volume, performing on level with the established methods WD and CM.