The number of people in Spain registered as unemployed crept up by 19,720 in September from the August level to 4,447,650 in September, the figures from the employment ministry showed.
August and September usually see a rise in registered unemployment as temporary summer hires in the country's key tourism sector end.
"It is the weakest rise in registered unemployment in the month of September since 2007," the employment ministry said in a statement.
The number of registered unemployed crept up by some 8,000 in August, putting an end to six months of declines.
On a yearly basis, the number of unemployed, as measured by those signing on at government offices, was down by 276,705 people from September 2013.
The registered unemployed list is a different measure from the benchmark quarterly unemployment rate published by the national statistics institute.
The institute recorded 5.5 million unemployed in Spain in June, yielding an unemployment rate of 24.47 percent.
That was lower than the previous quarter but still one of the highest rates in the developed world, second only to Greece in the eurozone.
The high figure reflected the lingering impact of the busting in 2008 of a building boom, which sparked five years of stop-start recession in the eurozone's fourth-biggest economy.
Spain emerged timidly from recession in mid-2013 and in the second quarter of this year posted its strongest quarterly growth since 2007, expanding by 0.6 percent.
The government on Friday raised its growth forecasts for this year and the next.
It now sees the economy expanding by 1.3 percent in 2014 and by 2.0 percent in 2015.
The government expects Spain's unemployment rate will ease to 24.2 percent by the end of 2014 and drop to 22.2 percent at the end of 2015.