Abstract Objectives We compared the accuracy of shorter-time dual-phase 18F-FDG PET/CT in evaluating 94 different lung nodules classified as solid or ground-glass nodules (GGNs). Materials and Methods Early and delayed maximum standardized uptake values (SUVmax) as well as the retention index (RI) of each nodule were determined in 75 solid nodules and 19 GGNs. Results In solid nodules, early SUVmax, delayed SUVmax, and RI were higher in malignant than in benign lesions. In GGNs, these values were not significantly lower in the malignant than in the benign lesions. Conclusion In the patient group with solid nodules, shorter-time dual-phase 18F-FDG PET/CT could significantly differentiate the malignant from the benign ones.