Missed outpatient appointments have cost Horsham Hospital in Hurst Road nearly £600,000 since the start of 2010.
A Freedom of Information request submitted by the County Times to NHS Sussex revealed that patients have cost Horsham Hospital a notional £598,279.19 because they failed to turn up for a total of 6,400 appointments, wasting NHS resources.
It averages almost seven appointments per day, costing £638.50 per day, at an average of £93.50 lost per appointment.
NHS Sussex allocates part of its budget to hospitals such as Horsham for services such as outpatient appointments.
First appointments are more expensive and are more costly for the hospital and trust.
During 2010 missed appointments cost Horsham Hospital £184,064.62, rising to £269,963.83 in 2011.
So far the total for 2012 is £144,250.72.
The data refers to outpatient appointments only as there is no numbers available for GP surgeries for individual areas.
An NHS Sussex spokesperson said: “The financial data given is indicative only - if an outpatient appointment is missed the pertinent hospital receives no payment for this.
“This should not be interpreted as an actual additional cost to the NHS.
“Whilst missed appointments are inefficient, NHS organisations and staff ensure that unexpected gaps in clinics are used for essential administrative work or in additional time spent with patients with more complex issues.”
There were more than 400,000 missed appointments since 2010 across the whole of NHS Sussex, with a notional cost of £36,759,459.21.
The spokesperson added: “Missed appointments have a significant impact on local health services. They affect how quickly we can see and treat people, how soon people are diagnosed and how long other patients may have to wait for an appointment. It also means an additional cost to the NHS for the time that has not been used effectively to provide patient care.
“We know that sometimes there are good reasons why people can’t make their hospital or GP appointments, but it would always be appreciated if people could call their hospital or GP surgery to rearrange or cancel if they know they are not able to attend.
“That way the appointment can be offered to another patient, helping to keep waiting times shorter and also making sure that doctors and nurses use their time more effectively.”