Marijuana generally refers to the dried mixture of leaves and flowers of the cannabis plant, and the term cannabis is a commonly used to refer to products derived from the Cannabis sativa L. plant. There has been an increasing interest in the potential medicinal use of cannabis to treat a variety of diseases and conditions. This review will provide the latest evidence regarding the medical risks and potential therapeutic benefits of cannabis in managing patients with sleep disorders or those with other medical conditions who commonly suffer with sleep disturbance as an associated comorbidity. Published data regarding the effects of cannabis compounds on sleep in the general population, as well as in patients with insomnia, chronic pain, posttraumatic stress disorder, and other neurological conditions, will be presented. Current trends for marijuana use and its effects on the economy and the implications that those trends and effects have on future research into medical cannabis are also presented.