The average salary for a job advertised in Preston is now £3,928 less than the national average of £28,407.
New figures have been calculated for the area by jobs search engine AllTheTopBananas.com in its February salary index.
It has worked out the average advertised salary in Preston is now £24,479.
London figures have been stripped out for the first time to give more accurate results.
AllTheTopBananas.com crunched data from 2,942 jobs in Preston advertised over the last six months.
They are part of 880,000 jobs studied from around the country to get the UK average.
The jobs were advertised between August 2007 and January 2008.
Dave Martin, the MD of AllTheTopBananas.com, said: "Now that London figures have been stripped from the data, it gives a much more realistic view of the average salary here in Preston.
"It's fascinating to know how Preston performs against other areas.
"AllTheTopBananas.com publishes this information every month as part of our mission to be the UK's most helpful jobs website."
AllTheTopBananas.com has access to a huge amount of jobs data.
It gathers, collects and displays jobs from hundreds of partner websites across the UK.
Right now the site has 244,863 vacancies online.
It releases a salary index every month, which contains a regional breakdown and figures for the top 50 towns and cities in the UK.
The Monthly Salary Index is online via the link below.