The jobless rate climbed from 25.02 percent the previous quarter, reaching the highest level since Spain returned to democracy after the death in 1975 of General Francisco Franco.
The result shattered even the modest expectations of Prime Minister Mariano Rajoy's government, which had been forecasting an unemployment rate of 24.6 percent by the end of 2012. It is a very, very high figure, said Soledad Pellon, market strategist at IG Markets in Madrid. The expectation is that this figure will carry on growing during 2013. This year will still not be a year in which we will see job creation, she said.
International markets expected the Spanish unemployment rate to peak at 27 percent in the next two years, Pellon said, forecasting that the rate could hit 26.8 or 26.9 percent in 2013.
An extra 187'300 people joined the jobless queue, which reached a total of 5.97 million people in the final quarter of 2012, a National Statistics Institute report showed.
There were 8.33 million Spanish households in which every potential worker was unemployed, it said.
The story for young people was even grimmer: the unemployment rate for those aged 16 to 24 soared to 55.13 percent, up from 52.34 percent the previous quarter.
Millions of Spanish workers lost their jobs in the wake of a 2008 property crash, which brought the construction industry to a halt and left the country's finances in a mess, and the labour market has yet to recover.
Spain, the fourth-biggest economy in the 17-nation single currency area, has since embarked on a programme of spending cuts and tax rises to save 150 billion euros between 2012 and 2014, prompting mass street protests.
The government has vowed to lower the public deficit from the equivalent of 9.4 percent of annual gross domestic product in 2011 to 6.3 percent in 2012, 4.5 percent in 2013 and 2.8 percent in 2014.
But the budget squeeze has hurt economic activity.
In recession since the end of 2011, the economy contracted by about 0.6 percent in the latest quarter, its steepest dive in more than three years, according to a separate report this week by the Bank of Spain.
The Spanish economy suffered as a buying spree ahead of a September 1 sales tax increase evaporated in the final quarter, it said.
At the same time, public sector workers had their Christmas bonuses cancelled.
Tough financing conditions in the midst of a crisis in the banking sector further crimped activity. Spain's bad loan-laden banks are undergoing a drastic restructuring with the help of a European Union rescue loan of up to 100 billion euros.
Over the whole of 2012, the Bank of Spain said economic output fell by 1.3 percent from the previous year. That was slightly better than the government's forecast for a 1.5-percent contraction.
What is also worrying the government is that the rate of unemployment for people under the age of 25 has now reached 60 percent, according to officially released figures.
When Rajoy took office in late 2011 there were 5.27 million jobless in Spain.
The economic downturn has put an average of 1'900 out of work every day through 2012 and with the recession expected to last at least until the end of 2013, net job creation is unlikely this year.
In comparison to the Spanish unemployment rate, Britain's jobless level for those aged 16-24 was 20.5 percent in the period September to November in 2012. That level was unchanged compared with the previous quarter and down 1.7% compared with a year earlier and unions here in the Balearics can not see the situation improving this year.