Background: Little evidence exist associating displaced sternal fractures with blunt cardiac injury (BCI), especially regarding the depth and severity of sternal fracture displacement and risk of BCI. The purpose of this study was to quantify sternal fracture severity by the degree of displacement and to evaluate the association of fracture severity with BCI. Materials and methods: A single institution retrospective review was performed from 2011 to 2014. All adult patients with sternal fracture were identified from the trauma registry, and sternal fracture displacement was quantified as mild (>0 mm, <5 mm), moderate (≥5 mm, <10 mm), or severe (≥10 mm). BCI was diagnosed according to standard AAST grading. Analysis was performed to assess the association of sternal fracture displacement with BCI, which was the primary outcome of interest. Results: Two hundred thirty-five patients with sternal fractures were included in the study. Forty-five percentage of patients suffered a displaced fracture, and 42.6% were diagnosed with BCI. There was no difference in mean fracture displacement when compared to patients without BCI (2.4 versus 1.6 mm, P = 0.07). There was no significant increase in BCI with sternal fracture displacement when compared to patients with nondisplaced fractures (44.3% versus 41.1%, P = 0.62). Neither fracture displacement (OR 1.10, CI 95% 0.65-1.88) nor severe displacement (OR 2.34, CI 95% 0.64-8.54) was associated with significantly increased risk of BCI. Conclusions: There is no significant association between the depth of sternal fracture displacement and BCI. Further evaluation and management for BCI should be reserved in the absence of additional symptoms or findings.