Those under 25 tend to miss their appointments more often
Patients who miss appointments are costing NHS North East £24m a year.
It equates to a total of about 270,299 missed hospital appointments, which in turn slows down the referral time for further treatment.
People in Northumberland and Newcastle have the worst record, with 98,141 not showing every year.
Ian Dalton, chief executive of NHS North East, said: "We're trying hard to improve our services but we need people to work with us."
In a bid to raise awareness, the North East Strategic Health Authority has started a campaign by using a TV commercial, information leaflets, bus shelter adverts and a mobile advertising van travelling around the region.
An NHS spokesman also said that the problem of missed appointments appears to be more prevalent among younger people, particularly those aged under 25.
Mr Dalton added: "We know that sometimes there are good reasons why people can't make their hospital or GP appointments, but what we are asking is that people call their hospital or GP surgery to rearrange or cancel.
"The message is, 'keep it or cancel it, don't waste it'."