The target waiting time for referrals is 13 weeks, but some patients must wait considerably longer.
The health and social services department tries to see patients within three months of being referred by their GP.
For some problems, such as sports injuries, diabetes or general surgery, the average wait is about six months.
Figures released by Jersey's health department show some patients referred to the hospital for bariatric surgery are having to wait over four years for treatment.
Data released by the department has shown that less than a third of specialist areas have a waiting list longer than the target.
But women needing to see a specialist before giving birth are able get an appointment right away after being referred by their GPs.
People with back pain, adult mental illness or needing breast surgery, also have less than a month to wait before they are able to see a specialist.
People who need to see specialists at Jersey hospital for obesity problems face an average of a four-year wait.