Type 2 diabetes (T2D) is now considered a pandemic noncommunicable disease, and the prevalence is still increasing steadily worldwide. Several lines of evidence, including T2D, is an aging-related disease, and the phenomenon of the metabolic memory and developmental origins of adult diabetes argues that epigenetic disorder plays critical roles in the development of T2D. Environmental factors can affect epigenetics during early fetal life until adulthood. Altered epigenetics can be maintained during mitosis and meiosis, so that the subsequent response to environmental cue in later life has also been altered. Epigenetic aberra-tions affect miRNA expression and functions, and altered miRNA expression can also affect expression of many genes including those relevant to epigenetics. Thus, the development of T2D is an accumulative process that may involve complex interactions between altered transcription factors, miRNA functions, and increased epigenetics disorder in response to environmental stimuli during different stages of life. Type 2 diabetes (T2D) is now considered a pandemic noncommunicable disease, and the prevalence is still increasing steadily worldwide. Several lines of evidence, including T2D, is an aging-related disease, and the phenomenon of the metabolic memory and developmental origins of adult Diabetes argues that epigenetic disorder plays a critical role in the development of T2D. Environmental factors can affect epigenetics during early fetal life until adulthood. Altered epigenetics can be during during and disease, so that the subsequent response to environmental cue in later life has also been altered. Epigenetic aberra-tions affect miRNA expression and functions, and altered miRNA expression can also affect expression of many genes including those relevant to epigenetics. Thus, the development of T2D is an accumulative process that may involve complex interactions between altered transcription factors, miRNA functions, and increased epigenetics disorder in response to environment al stimuli during different stages of life.