Aim: Bleomycin is an antitumor antibiotic used successfully to treat a variety of malignancies, predominantly germ cell tumors and Hodgkin's lymphoma (HL). The major limitation of bleomycin therapy is the potential for life-threatening interstitial pulmonary fibrosis. Early identification of asymptomatic patients who may develop toxicity is important. We aimed to evaluate fluorodeoxyglucose positron-emission tomography (FDG-PET/CT) findings to predict bleomycin toxicity (BT) early after chemotherapy with doxorubicin, bleomycin, vinblastine, dacarbazine (ABVD) chemotherapy before clinical symptoms and radiological changes occur. Materials and Methods: HL patients who were treated with ABVD were evaluated. SUVmax values of lung parenchyma were analyzed in FDG-PET/CT at diagnosis and after 4 cycles of chemotherapy in all patients. At the end of the chemotherapy cycles, lung parenchymal SUVmax values of patients with BT and without BT were compared statistically. Results: Twenty (66.7%) male and 10 (33.3%) female patients with HL were included. Five (16.7%) HL patients developed BT. In 3 HL patients, BT was determined after 5 cycles and in 2 patients, BT was seen after 6 cycles. In all 5 of these patients with BT, FDG uptake in PET-CT was increased after 4 cycles of chemotherapy and BT was predicted before clinical and radiological findings by FDG-PET/CT. After 4 cycles of chemotherapy, lung parenchymal SUVmax of patients with BT (3.24 +/- 0.76) was significantly higher than in patients without toxicity (1.84 +/- 0.52) (p < 0.001). In patients with BT, a significant increase was established in lung parenchymal SUVmax after 4 cycles of chemotherapy when compared to the time of diagnosis (p = 0.043). Conclusion: BT can be fatal. Early detection of BT is essential in clinical practice. FDG-PET/CT can predict BT before clinical and radiological findings occur.