Docetaxel (DOC) is one of the most effective agents for breast cancer treatment. Here, we report docetaxel-induced severe hypertriglyceridemia in a patient previously diagnosed with hyperlipidemia and corresponding therapeutic intervention. A postmenopausal woman, with previously controlled hyperlipidemia using rosuvastatin 5 mg daily, was diagnosed with stage IIB breast cancer with human epidermal growth factor receptor-2 overexpression; she received DOC (75 mg/m<sup>2</sup>), pertuzumab, and trastuzumab treatment as neoadjuvant chemotherapy. The serum triglyceride level was mildly higher than normal, and cholesterol level was normal at baseline. The serum triglyceride level was almost stable after chemotherapy initiation but suddenly increased to grade 3 (770 mg/dL) after the third cycle of the treatment without any symptoms. Sustained-release bezafibrate 400 mg was administered, resulting in a significant decrease to the baseline level; bezafibrate was discontinued on day 28 of the fourth chemotherapy as neoadjuvant chemotherapy was completed. The level was stable around the baseline level during adjuvant chemotherapy with pertuzumab and trastuzumab. Therefore, DOC-induced severe hypertriglyceridemia was strongly indicated in this case. The mechanism underlying the symptoms remains unclear; we speculate that it could be a resultant of a decrease in lipid metabolism as the patient had grade 2 diarrhea. Moreover, her backgrounds, such as mild hypertriglyceridemia, postmenopausal, diabetes, and obesity, in addition to DOC administration might have affected the outcome. Fibrate administration and cessation of treatment were as effective as in previous reports. DOC-induced hypertriglyceridemia presents with the possibility of severe complications. Elucidation of the exact mechanisms and epidemiological features is required for better management.