Move over, Boston and Silicon Valley. Washington and Baltimore have arrived.

For the first time, the Baltimore-Washington region leads the nation in the number of people working for computer companies, according to a report released yesterday by an area economic-development group. The high-tech meccas of Silicon Valley and Boston ranked fourth and fifth, respectively, the study by the Washington/Baltimore Regional Association found (WBRA).

The report, called the Computer Services Fact Sheet, said there are 69,867 computer services employees in the local region, up 61 percent from 1987, when the previous report was released. These companies offered everything from data processing services to equipment rentals.

The Washington-Baltimore region finished just ahead of the Greater New York region, which had 69,606 computer service employees in an area that also includes northern New Jersey. The latest figures were based on 1987 Census Bureau statistics.

Computer services companies in the area also had healthy sales, second only to the New York region. That area was first with $6.5 billion in sales, or 11.8 percent of the national total of $54.1 billion. The Baltimore-Washington region rang up $5.7 billion in sales, or 10.6 percent of the national total and a 137 percent jump from the level in the 1987 report. Boston and Silicon Valley didn't do much better in this category, finishing third and fifth, respectively.

"This probably moves the region up a couple of pegs from lower first rank to middle first rank," said WBRA Chairman Benjamin Civiletti, managing partner of Venable, Baetjer and Howard, a Baltimore law firm. "It certainly puts us on the same conversational levels as Silicon Valley and Route 128 {Boston}. It shows we're much larger, stronger and more on the cutting edge than the average guy on the street would have thought."

Civiletti said he was surprised that so many people worked for computer services firms in this area and that total receipts were so high.

"This is going to have a major impact both inside and outside the industry," he added. "Silicon Valley and Route 128 know we're for real."

Not everyone sees it that way.

"To compare Washington-Baltimore with Silicon Valley and Boston is just not right yet," said Frank Florence, a vice president for the San Jose market research firm Dataquest. For Washington to truly move into the ranks of its peers, it needs a heavier computer manufacturing presence, he said. "Until it does, you can't compare it with the other two."