Thomas M. Bradley, the head of Maryland's AFL-CIO, is a confident man these days.

More than 90 percent of the legislative candidates his union group supported in last month's election were victorious, while several of labor's bitterest and most powerful enemies went down to defeat, circumstances that will give a more prolabor cast to the 1983 General Assembly than anyone can remember.

Gov. Harry Hughes, one of those aided by AFL-CIO election efforts, has promised to satisfy a long-held desire of labor by setting up a separate department for labor issues. Legislative leaders are working overtime to draw up jobs-related bills important to the unions. And just this week, the conservative senator who ruled the state Senate for the last four years was deposed by his colleagues in favor of a liberal, labor-oriented lawyer for whom union leaders had strongly lobbied.

"Labor's clearly in the ascendancy," said Hughes' chief of staff, Ejner J. Johnson. State Sen. Laurence Levitan (D-Montgomery) added, "They don't have to go to a health club any more because they've got so many muscles."

All of this is good news to Bradley, who says he believes labor may finally achieve its most cherished goal -- collective bargaining for state employes -- when the legislature convenes in January. Many legislators agree with Bradley's assessment and even Hughes has said he would likely approve such a measure if it left out binding arbitration and the right to strike.

Bradley and other union leaders, along with sympathetic legislators, attribute the more hospitable climate in part to the difficult economic times. "I think people are coming back to Annapolis more sensitive to these issues," Bradley said. "I think we will be treated with greater fairness."

But the larger factor may well be the election effort put on by the unions for last September's primary and November's general elections -- the most substantial and organized election push ever by the union, according to Bradley.

The AFL-CIO poured $30,000 into legislative races, found candidates to run against incumbents it wanted to oust, and mailed district-by-district brochures in favor of its candidates. It then sent the union-supported candidates letters detailing AFL-CIO efforts on their behalf.

Those measures were credited with helping unseat the Republican minority leader, Sen. Edward J. Mason, a staunchly antiunion Western Marylander, in the GOP primary, and the powerful antiunion chairman of the House Appropriations Committee, Del. John R. Hargreaves, last month.

"Hargreaves single-handedly killed collective bargaining last year by sticking the bill in his pocket and not letting it onto the floor," said Bradley.

According to Bradley's calculations, just under half of the 47 state senators in the upcoming legislature are prolabor and a working majority of 28 or 29 are considered sympathetic to labor-related issues. Similar figures are not yet available for the 141-member House of Delegates, but that body has generally been supportive of labor-oriented measures.

"They went out very hard to elect people they could control," said state Sen. Edward Thomas (R-Frederick), who successfully fended off labor efforts to unseat him.

Indicative of labor's new influence was the recent fight for the Senate presidency. Incumbent James Clark Jr., a Howard County farmer, was opposed by Sen. Melvin A. Steinberg, a Baltimore County lawyer whose clients have included several unions.

The contest was a standoff until labor persuaded several members of the black caucus to switch from Clark to Steinberg, paving the way for Steinberg's victory.

In addition to collective bargaining and a new department of employment and training, as Hughes intends to name it, Bradley said union leaders will push for an increase in unemployment benefits. They also hope to win support for a bill to close loopholes in prevailing wage laws that require employers who receive state contracts to pay the most frequently occurring--and usually union--wage in the labor market where the work is being done.

Hughes, in one of his few campaign promises, said he would submit such legislation on behalf of the unions.

One of the tougher battles for the unions will be to win raises for state employes. Hughes, who is grappling to fill a projected $61 million shortfall in next year's budget, has already said he is not certain there will be enough money to include raises in his budget.