Background: Movement loss, reduced function, pain, and lymphedema are frequent problems following breast cancer surgery. Axillary web syndrome (AWS) is a condition that develops after breast surgery and appears as a cord causing pain and movement loss and has been considered a possible risk factor for lymphedema. There are no reported imaging correlates of AWS in the literature. This study ascertained the clinical and ultrasonographic characteristics of AWS. Methods: Patients with surgical breast cancer (n=36) were assessed for shoulder range of motion (ROM), lymphedema, function, pain, and psychological issues at 2 weeks, 4 weeks, and 3 months. Subjects with AWS had an 18 MHz ultrasound of the cord. Analysis: A repeated measures ANOVA compared the AWS and non AWS groups across visits. Univariable and multivariable logistic regression identified AWS risk factors. A sign test was used for ultrasound analysis. Results: Seventeen subjects were identified with AWS with ten subjects having AWS at 3 months. There was an interaction effect in shoulder abduction with active ROM and passive ROM being statistically lower in the AWS group at 2 and 4 weeks. There was an interaction effect in upper extremity lymphedema tissue dielectric constant (TDC) measures with the AWS group having initially higher measures then decreasing which was opposite of the non AWS group. Both groups indicated trunk edema on the chest wall using TDC measures. Functional, psychological, and pain measures had no group or interaction effect. Younger age, low BMI, and higher number of lymph nodes removed were identified as significant risk factors for AWS. The strongest predictor was identified as BMI. There were no significant differences in ultrasonographic characteristics. Conclusion: The onset of AWS is often within weeks after surgery but later onset is possible. Cords do not resolve in all subjects by 3 months. Greater early movement restriction is evident in subjects with AWS though neither group achieved full pain free motion. There were no differences in early edema measurements between groups, but both groups indicated trunk edema at 3 months. Low BMI was a risk factor for AWS. An identifiable structure was not found using an 18MHz ultrasound.