Objective To investigate the clinical features and electron transfer flavoprotein dehydrogenase (ETFDH) gene mutations in 35 Chinese patients with lipid storage myopathy. Methods The clinical data of 35 cases with lipid storage myopathy confirmed by muscle biopsy were collected. The sequences of all 13 exons of ETFDH were analyzed. Results All 35 patients showed proximal weakness. Ten of them demonstrated masseter weakness and 28 of them showed weakness in neck flexion. Twenty-nine of 32 patients who were followed up showed improvement after treatment with VitB2 and CoQ10. Mutations of ETFDH were found in 30 of 35 patients,which included 8 homozygosises,20 compound heterozygosises and 2 single heterozygosises. Fourteen novel mutations were found, including 9 missense mutations ( c. 3G > C, c. 152G>A, c. 191G > A, c.349G>C, c.433G>C, c. 949C > A, c. 1454C > G, c. 1744A >T and c. 1763A>G), 1 nonsense mutation(c. 172G>T), 2 deletions(c. 1282_1283del and 1773_1774del) and 2 splice mutations (c. 405 + 1G > T and c. 1691 -3C > G). Nine of them showed c. 250G > A mutation and 6 of them showed c. 770A > G mutation. Conclusions Lipid storage myopathy is presented as proximal weakness. Multiple acyl-CoA dehydrogenase deficiency caused by mutations of ETFDH is the major cause of lipid storage disease in this group. ETFDH c. 250G > A and c. 770A > G mutations show a high frequency.