Abstract Serum lipids have been found to play important roles in the pathophysiology of mood disorders. The aim of the present study was therefore to investigate the relationship between symptom dimensions and serum cholesterol and triglyceride levels, and to explore correlates of lipid levels during acute mood episodes of bipolar I disorder in Taiwan. Measurements were taken of the serum cholesterol and triglyceride levels in patients with bipolar I disorder hospitalized for acute mood episodes (68 manic, eight depressive, and six mixed). The relationships between serum lipids levels and various clinical variables were examined. The mean serum levels of cholesterol (4.54 mmol/L) and triglycerides (1.16 mmol/L) of sampled patients were comparable to those of the general population in the same age segment. Severe depressive symptoms and comorbid atopic diseases were associated with higher serum cholesterol levels. A negative association was noted between serum triglyceride levels and overall psychiatric symptoms. Compared with previous studies on Western populations, racial differences may exist in lipids profiles of bipolar disorder patients during acute mood episodes. Increased serum cholesterol levels may have greater relevance to immunomodulatory system and depressive symptoms, in comparison with manic symptoms.