Purpose To evaluate the use of functional Near-Infrared Spectroscopy (fNIRS) in the evaluation of overall microvascular foot perfusion in diabetic foot ulcers (DFU) to predict wound healing. Methods Patients with DFUs were recruited to a prospective study, with fNIRS measured using MOORVMS-NIRS and correlated with wound dimension changes monitored using Silhouette Wound Imaging technology. fNIRS measures of oxygenated (O2Hb) and deoxygenated (HHb) hemoglobin, as well as calculated oxygen saturation (SaO2) was performed in three phases, (1) at rest whilst sitting reclined at 45 degrees, (2) with toe and ankle flexion movements at 40bpm, (3) at rest after toe and ankle flexion. Each phase was measured for two minutes and mean values for each phase was calculated using the MOORVMS-PC software. Dynamic parameters of change in foot perfusion during flexion exercise versus baseline, and post-exercise versus baseline was calculated as a ratio, analysed with One-Way ANOVA. Results 60 patients were recruited in the study, one of whom died and three lost to follow up. Of the remaining, mean age was 65.4±12.6 years old, with male predominance (82.1%). When grouped into healing ulcers (n=21), non-healing ulcers (n=32) and deteriorating ulcers (n=3) over a 3-month follow up period, flexion to baseline O2Hb ratio was significantly lower in both non-healing (0.89±0.14U) and deteriorating (0.60±0.17U) groups, compared to healing (1.02±0.12), p<0.005. This trend was similar for post-flexion compared to baseline O2Hb (healing, 1.12±0.19U; non-healing, 1.03±0.14U; deteriorating, 0.85±0.15U, p=0.013). This relationship was similarly seen for HHb measures. Conclusion We present fNIRS as a novel, non-invasive method, to evaluate overall foot perfusion in diabetic patients. This is a potential method to evaluate higher-risk feet to predict wound healing and deterioration in DFUs. This user-friendly platform could complement current bedside measures of ankle-brachial and toe pressure indices.