“Marijuana is used by millions of people, with use likely to increase in the USA because of the trend towards increased decriminalization and legalization. Obesity and diabetes mellitus (DM) rates have increased dramatically in the USA over the past 30 years, with a recent estimate of 29 million individuals with DM. Because there is a plausible link between marijuana use and diabetes due to the known effects of cannabinoids on adipose tissue and glucose/insulin metabolism, it is important to study and understand how marijuana use is related to obesity and diabetes. This paper provides background on the human endocannabinoid system and studies of the association of marijuana use with body mass index/obesity, metabolic syndrome, prediabetes, and diabetes. The studies to date have shown that marijuana use is associated with either lower odds or no difference in the odds of diabetes than non-use.”