This study reported a family of mitochondrial diabetes mellitus complicated with chronic hereditary pancreatitis. A 18-year-old woman presented with self-reported hyperglycemia and chronic epigastric pain was admitted to our hospital. Clinical data and family history were collected. Mitochondrial gene sequencing and whole exon gene sequencing showed that the proband carried mutation of mt.3243A>G and heterozygous mutation of SPINK1 c. 194+ 2T>C, which was considered as mitochondrial diabetes mellitus with chronic pancreatitis.