Some people in England are facing waits of nearly two-and-a-half years for an NHS hearing aid, the RNID charity says.
There are 9 million deaf and hard of hearing people in the UK
Among 99 primary care trusts, it found 10 were not treating people within a year, with the longest wait of 125 weeks in Kingston-upon-Thames, London.
The average wait for treatment was 22 weeks and the shortest four weeks. The RNID urged the government to do more to meet a pledge of 18-week maximum waits.
The government said some waits were too long but progress was being made.
Health Minister Ivan Lewis has pledged that by December 2008 all patients with hearing or balance problems that require care from a hospital consultant will be treated within 18 weeks.
And all other patients with routine hearing loss should be assessed within six weeks.
The RNID wrote to England's 152 primary care trusts to assess the situation and among the 99 that replied, the average wait for a hearing aid was 22 weeks, affecting 28,384 people.
Sixty-six PCTs said they were providing treatment within 18 weeks.
Patients at the Norfolk and Norwich PCT, Southampton City PCT and Bolton PCT were treated within four weeks.
But there were waits of over one year in nine PCTs other than Kingston-upon-Thames - Suffolk (78 weeks), Gloucestershire (72), Tyne and Wear: Washington Health Centre (68), Ealing (67), Havering (64), Tyne & Wear: Sunderland Royal Hospital (62), Shepway (58), Mid Essex (56) and South Tees (54).
RNID director of communications Brian Lamb said: "Despite government assurances, an 18-week target is a distant dream for thousands of people waiting over a year for their first hearing aid, who are battling isolation and depression because of their hearing loss.
"RNID wants the government to do more to end this scandal, by putting pressure on local health chiefs to take hearing-health seriously and bring down waiting times."
A Department of Health spokesman said: "We acknowledge that audiology waiting times in parts of the country are too high, and that is why we recently published a national framework which sets out the tools the local NHS needs to transform this service.
"The framework was developed following extensive work with a range of stakeholders including NHS audiologists, professional bodies and the RNID."