Purpose To perform a retrospective review to determine whether maximum standardized uptake values (SUV max) from staging 2-deoxy-2- [ 18F] fluoro-D-glucose (FDG) positron emission tomography/computed tomography (PET/CT) studies are associated with outcomes for early-stage non–small-cell lung cancer (NSCLC) treated with stereotactic body radiotherapy (SBRT). Methods and Materials Seventy-two medically inoperable patients were treated between October 17, 2003 and August 17, 2007 with SBRT for T1-2N0M0 NSCLC. SBRT was administered as 60 Gy in 3 fractions, 50 Gy in 5 fractions, or 50 Gy in 10 fractions using abdominal compression and image-guided SBRT. Cox proportional hazards regression was performed to determine whether PET SUV max and other variables influenced outcomes: mediastinal failure (MF), distant metastases (DM), and overall survival (OS). Results Biopsy was feasible in 49 patients (68.1%). Forty-nine patients had T1N0 disease, and 23 had T2N0 disease. Median SUV max was 6.55 (range, 1.5–21). Median follow-up was 16.9 months (range, 0.1–37.9 months). There were 3 local failures, 8 MF, 19 DM, and 30 deaths. Two-year local control, MF, DM, and OS rates were 94.0%, 10.4%, 30.1%, and 61.3%, respectively. In univariate analysis, PET/CT SUV max, defined either as a continuous or dichotomous variable, did not predict for MF, DM, or OS. On multivariable analysis, the only predictors for overall survival were T1 stage (hazard ratio = 0.331 [95% confidence interval, 0.156–0.701], p = 0.0039) and smoking pack-year history (hazard ratio = 1.015 [95% confidence interval, 1.004–1.026], p = 0.0084). Conclusions Pretreatment PET SUV max did not predict for MF, DM, or OS in patients treated with SBRT for early-stage NSCLC.