Positron Emission Tomography (PET) with F-18-fluorodeoxyglucose is commonly used in the evaluation of lung nodules; however, there is limited data on the PET appearance of coal worker's pneumoconiosis (CWP) and its utility for diagnosing lung malignancy in this setting. Six cases of CWP and suspected malignancy are reported. Each patient had at least one nodule >1 cm in diameter for a total of 19 nodules >1 cm. On PET imaging 18 of the 19 nodules were hypermetabolic and five of the six patients had at least one nodule that was PET positive. Based on pathologic data and clinical follow-up, none of the six patients had any evidence of malignancy. In this series, PET imaging was often positive in patents with CWP; however, all were false positives with standardized uptake value measurements in the range that are typically seen with malignant nodules. Due to its high rate of false positives, PET imaging seems to be of limited utility in diagnosing malignancy in patients with underlying coal worker's pneumoconiosis.