Pre-tax profit fell 49.7% to Â£27.7m in the first half of the year ending 30th June,
The firm said its focus for the period had been operational improvements, which meant its "financial performance would inevitably lag behind".
Ladbrokes boss Richard Glynn said it was now "well positioned for growth".
"We have made substantial progress. We now have the products, the platforms, the people and the brand in place to deliver," he added.
Ladbrokes formed a tie-up with software developer Playtech last year and as a result switched its gaming products to a new system.
The firm admitted the switch over had caused more disruption than expected, but said it was now complete.
Ladbrokes said it had also completed the replacement of 9,000 of its gaming machines with more sophisticated models.
It also closed 46 of its "under performing" shops in the first half, nearing its target of 50 for the year. It said further shop closures beyond this were "inevitable", but it was too early to specify the number.
The firm said its performance in the UK was hit by "industry-wide customer friendly results" in both the January football and horse racing in June.
And it said its adherence to the The Association of British Bookmakers (ABB) voluntary industry code of conduct had also had "a clear impact on revenues".
The code, which enables players to set spend and time limits on gaming machines, aims to promote responsible gambling.
However, it said its World Cup performance had been "strong" with bets on mobiles up 1,100%.
"The board remains confident of the outlook for the business and in delivering a result in line with its expectations for the current year," it added.
Shares in Ladbrokes rose 3% in early trading. Peel Hunt analyst Nick Batram said the fall in profit was in line with expectations.
"The results are unquestionably poor but they are in line with forecasts. It's also a positive narrative from Ladbrokes in that it has focused on all the things it is implementing to put it right," he added.

Insp Ken Mackaill and Det Sgt Stuart Hinton are accused of gross misconduct over accounts they gave of a meeting with Mr Mitchell, and could be sacked if the disciplinary charges are proved.
The meeting followed claims the Tory MP called police "plebs", which he denied.
Another officer, Sgt Chris Jones, has been cleared of misconduct.
Det Sgt Hinton is from Warwickshire Police, Insp Mackaill works for West Mercia Police and Sgt Jones for West Midlands police.
All three officers, who are Police Federation representatives in the Midlands, met the Conservative MP at his Sutton Coldfield constituency office in October 2012 to find out what he had said during a row in Downing Street.
It followed reports he had sworn at officers and called them "plebs" for refusing to let him cycle though the street's main gate.
After the meeting the men said Mr Mitchell had not given a full account and called for him to resign.
But a recording of the meeting cast doubt on what they had said.
The three officers then faced further criticism over evidence they gave to MPs before the home affairs select committee in October 2013.
Carl Gumsley, commissioner for the Independent Police Complaints Commission (IPCC), directed Warwickshire Police on Monday to hold a misconduct hearing for Det Sgt Hinton.
This was after the force declined to follow Mr Gumsley's earlier recommendation that there was a case to answer.
West Mercia Police had decided, in line with Mr Gumsley's opinion, that Insp Mackaill has a case to answer for gross misconduct, and he should therefore face a misconduct hearing.
In 2014, a High Court judge rejected a libel case brought by Mr Mitchell against the Sun newspaper, concluding that "on the balance of probabilities" he had called a police officer a "pleb".
Mr Mitchell has accepted he used bad language but said he had not used that particular word.
He paid Â£300,000 in legal costs after losing the case.
Last year, the High Court described a misconduct investigation into the actions of the trio as "lamentable" saying there was a "series of errors and irregularities".
The case was then referred back to the IPCC.
Bookmaker Ladbrokes has reported a sharp fall in profit, despite saying it had had a "good World Cup" performance.
[NEXT_CONCEPT]
Two police officers face misconduct hearings over the "plebgate" affair involving ex-chief whip Andrew Mitchell, the police watchdog has said.