Background: Transforaminal epidural steroid injections (TFESIs) and facet joint blocks can be performed under fluoroscopy or computed tomography (CT) guidance. The purpose of this retrospective cohort study was to compare patient radiation dose for lumbar TFESIs and facet joint blocks under CT guidance vs. fluoroscopic guidance. Methods: The primary outcome of this retrospective cohort study was the difference between the estimated effective dose (ED) of CT guidance and fluoroscopic guidance for TFESIs and facet joint blocks. Patients who had undergone these procedures with both CT and fluoroscopic guidance were eligible for this study. Dose-length product for CT-guided procedures and dose-area product for fluoroscopic-guided procedures were retrospectively collected and converted to ED. Within- or between-group comparisons were performed with appropriate nonparametric tests, using a P value of < 0.05 to indicate statistical significance. Results: The 42 patients included in this study underwent a total of 100 procedures. The median estimated ED differed significantly between CT-guided injections and fluoroscopic-guided injections (1.59 mSv (interquartile range [IQR] 0.78 to 3.09) vs. 0.19 mSv (IQR 0.11 to 0.30) (Wilcoxon signed rank test, P < 0.001). Conclusions: The study results suggest that TFESIs and facet joint blocks performed with CT guidance are associated with more than 8 times higher patient radiation dose exposure compared to fluoroscopic guidance. There needs to be more vigilance with regards to CT guidance in interventional pain procedures.