Patients at a Berkshire hospital are to be sent text messages to remind them to turn up for their appointments.
The service has been trialled in several departments
The £7,000 scheme will send texts 72 hours before an appointment with the date and time, reminding the patient to call if they want to cancel.
Out-patients at the Royal Berkshire Hospital miss 35,000 appointments each year and it costs £2 to rearrange an appointment, the hospital said.
The hospital hopes the scheme will cut non-attendance rates from 10% to 5%.
The service has been trialled in the maternity, gynaecology and paediatrics departments and will cover the whole trust, and a total of 350,000 out-patients, in six weeks time.
Ali Browne, Director for Patient Pathways at the Royal Berkshire NHS Foundation Trust said: "If a patient fails to attend a clinic appointment, it increases our overall waiting list.
"If a slot is left unused, it means that another patient could have been brought in earlier."
Ms Browne emphasised that the patients are not charged for the service, which is confidential and fully automated.
She said: "However, the success of the service is obviously entirely dependent on having patients' mobile phone numbers, a piece of information we currently do not routinely record.
"To make sure that the service works, it is vital that patients help us by giving us their mobile phone numbers."
The trust said the cost of re-making appointments came from the time spent accessing hard-copy patient records.
They said missed appointments costs the NHS millions of pounds each year.