NHS Direct in England is to close at the end of the financial year, it has been announced.
The service said in July it was pulling out of contracts to provide the 111 non-emergency number service due to financial problems.
NHS Direct initially won 11 of the 46 regional contracts for the 111 service, covering 34% of the population.
It pulled out of two services and said in July the remaining nine were "financially unsustainable".
The 111 service is run by different organisations in each area, including private companies and ambulance trusts, who will now take on NHS Direct's work.
In a statement, NHS Direct said its 111 staff and call centres were due to transfer to five ambulance trusts by the end of November.
NHS Direct used to be paid more than £20 per call when it ran the old 0845 number, which will officially cease in March.
The payment for the 111 service is around £7 to £9 per call.
The statement said: "No patient services will be affected by the board's decision, as we expect each of the services that NHS Direct is commissioned to provide beyond March 2014 to be transferred to other organisations, together with the staff who provide them."
The organisation said it would launch a formal consultation with staff on Monday but "it is hoped that the number of redundancies arising will be kept to a minimum through transfer and redeployment of staff to other organisations".
It said the decision to close had been reached in agreement with the NHS Trust Development Authority and NHS England.
Chair of NHS Direct Joanne Shaw said "The closure of NHS Direct marks the end of its 15 years of continuous innovation, during which time it has led the world in remote health assessment, advice and information.
"It is an enormous privilege to have been part of this journey, and I look back over my 10 years with NHS Direct with gratitude and respect for the staff who have created this exceptional service.
"I look forward to seeing other organisations take forward a number of the services developed by NHS Direct, and I wish them well as they exploit the ever-growing reach and power of technology, to provide value to patients and the NHS."
NHS Direct in Wales is unaffected by the announcement.
In the West Midlands, the West Midlands Ambulance Service NHS Foundation Trust will take on NHS Direct's work, with private firm Harmoni providing the service for the Worcester area and Staffordshire Doctors Urgent Care Ltd.
The North West Ambulance Service NHS Trust will take on the contract for the North West, while Somerset will be taken care of by the South West Ambulance Service NHS Trust.
Plans for London and Buckinghamshire are being finalised and will be announced shortly.
NHS England said its latest data showed a "significant improvement" in the 111 service compared with the period just after it launched in April.
Some 94.1% of calls are answered within 60 seconds, 92% of callers say they are satisfied with the service and 0.5% of calls are abandoned, it said.
Overall, 93% of the population has the NHS 111 service.
The four areas not covered - Cambridge and Peterborough, North Essex, Bedfordshire and Luton and Cornwall - will be up and running by February.
Dame Barbara Hakin, deputy chief executive at NHS England, said: "NHS 111 is now a stable and improving service and we are confident it will continue to get better.
"It is no secret that we had a tough start.
"But I have been impressed by the way that the staff providing these services across the country have turned the situation around on behalf of the public.
"Now NHS 111 provides a good service with high levels of public satisfaction.
"Calls are answered promptly and more people are getting access to the service as we move to full coverage in February 2014.
"I am confident, and the public should be too, that these new providers of NHS 111 will be able to deliver a smooth transfer and a high quality, reliable 111 service.
"The public should not feel any detrimental effects.
"NHS 111 is now going from strength to strength and we are determined to keep that improvement on track."