Bone stress injuries (BSIs) are a common lower limb injury amongst active individuals. While magnetic resonance imaging (MRI) has historically been the imaging modality of choice, there is increasing evidence that ultrasound (US) can be a useful diagnostic tool for these injuries. The aim of this prospective, observational study was to evaluate the correlation between MRI and US findings in the diagnosis of lower extremity BSIs and to characterize the sonographic features 25 patients age 19-62 years old diagnosed with an MRI-confirmed BSI to the metatarsals or tibia underwent a diagnostic US of the affected area as well as the correlative, asymptomatic region on the contralateral limb. The primary outcome was whether or not an association existed between sonographic findings and the MRI grade of the stress injuries. Median age was 35 years, and 84% were females. The most common injury grade was a grade 1 (40%). On US evaluation, periosteal edema was most commonly seen (80% of patients). Subcutaneous hyperemia and callous formation demonstrated a significant correlation with grade 4 BSIs (p=0.03). US and MRI demonstrated variable agreement on imaging findings, with as high as 100% agreement on the presence of a cortical break and callous formation, and as low as 64% for periosteal thickening. In conclusion, this study demonstrated a relatively strong agreement between US and MRI findings seen with a BSI. However, US did not consistently predict injury grade. Therefore, our findings suggest that US may be considered as a screening tool for tibial and metatarsal BSIs.