A 33-year-old man with advanced testicular cancer underwent high-dose chemotherapy combined with peripheral blood stem cell transplantation. After administration of granulocyte colony-stimulating factor (G-CSF), multiple infiltrative erythema was identified on the face, thigh, and lower leg. A dermatologist diagnosed this as Sweet's syndrome caused by G-CSF; consequently G-CSF administration was stopped. When the skin lesions had improved, phlebitis was found at the injection site of the peripheral vein catheter. The patient then suffered from sudden left chest pain and dyspnea. Chest computed tomography showed the characteristic findings of septic pulmonary emboli (SPE). He was treated by the administration of vancomycin, fluconazole, and pazufloxacin mesilate. Although Sweet's syndrome and SPE are rare diseases, the presence of these diseases must be considered when performing chemotherapy for urological malignancy.