The NHS had been battling with large deficits
The NHS in England is heading for an estimated surplus of £1.75bn in the current financial year, official estimates predict.
The prediction from the Department of Health is based on data from the first three months of the financial year.
The department said the money would stay in the NHS, and be used to fund patient care.
But political opponents questioned whether taxpayers' money was being used effectively.
The surplus is predicted to be around 2% of the overall NHS budget for England.
In the last financial year, the NHS in England recorded a surplus of £1.658bn, following a deficit of £547m in 2006-07.
David Flory, director general of NHS finance, performance and operations, said: "This is an excellent start to the year for the NHS.
"A strong financial position backed by good progress on delivery will continue to ensure high quality services for patients."
The report also said the NHS was on track to meet its end-of-year target for no patient having to wait longer than 18 weeks from GP referral to treatment.
However, Norman Lamb, the Liberal Democrat health spokesman, said: "This forecast surplus begs the question whether taxpayers' money is being used effectively.
"What evidence is there that trusts are using their surpluses to prepare for fluctuations in demand and investment in new services? Is this the NHS preparing for a period of slower growth in funding? Or is this individual trusts building up a surplus so that they can survive in a more competitive environment?"
Mr Lamb said that many areas of patient care, such as public health, alcohol treatment and mental health services, were being starved of funds.
"Several reports have shown that the current funding system risks damaging quality in the NHS but has done nothing to improve efficiency.
"Ministers should focus on sorting this out rather than patting themselves on the back for allowing the NHS to bank more and more cash."
Andrew Lansley, the shadow health secretary, said: "There continue to be hospitals whose finances are far from stable, as we can see from the number of primary care trusts who are rationing access to medicines.
"The government should explain why money voted in by Parliament for healthcare is not being used to make sure patients get the medical treatment that they need."