The jobless total fell by 58,216 to 4,094,770, the ministry said, adding that unemployment has fallen over eight percent over the past 12 months.
In the past year Spain, which ended 2015 with an official jobless rate of 20.9 percent has seen unemployment fall by 357,169.
Those included 43,416 people aged under 25, equivalent to an 11.1 percent fall for a category which has been particularly hard hit in recent years.
February had seen a small rise overall notably due to joblessness in the agriculture sector.
The number of economically active people as registered with social security was up 472,998 higher in March compared with a year earlier at 17.31 million, the ministry said.
The services sector, employing 13.16 million people, saw an improvement, notably with a 57,348 rise in hotel-related employment over February aided by Easter, a major holiday period in Spain, falling in March.
There were also small improvements in industry, construction and agriculture, although the proportion of jobless who have never worked rose 1.03 percent, the National Statistical Institute (INE) said.
INE tracks people who are looking for work rather than just those registered with job agencies.
According to their figures 4.78 million Spaniards were out of work at the end of 2015.