Thousands of souvenir vendors who swarmed the Washington Mall hoping to capitalize on the projected million or more keepsake-hungry persons drawn to the mass yesterday came away with mixed blessings from the visit of Pope John Paul II.

There appeared to be hundreds of losers among those who had paid $42 for a D.C. vending license, only to find a relatively sparse crowd, stiff competition and unsympathetic policemen who chased many of them from the most densely populated portions of the Mall.

Most of the winners appeared to be well-organized, like Paul Diabrosia of Hamden, Conn., who hired nine men and followed the papal entourage from Boston to New York, Philadelphia, Chicago and then to Washington. Diabrosia, who got to Washington Friday night, too late to apply for vending licenses, said he probably made $20,000 during the last week.

"We worked on the sneak," said Charles Jaspar, who was arrested for vending without a license.

But other vendors who came from out of town said they had not done so well. John Bauer, a vendor who said he also had followed the pope from Boston, said business was "very bad."

"This (Washington) was the worst. We're all stuck with tons of material, . . . $18,000 to $20,000 worth of merchandise," said Bauer. "This is a dumping ground here."

Even before the mass began, dozens of vendors marked down $2 buttons bearing the pope's visage to three for $1.

"Man, this isn't like home," said Joe Torres of Chicago. "I've cut prices in half, and I still can't sell anything."

Some people apparently grew annoyed at the intrusion of many vendors, who continued to hawk their trinkets in booming voices during the mass.

"Someone was actually trying to sell bumper stickers right during the homily," said Kate Padgen, as she left the mass before it was half over. "My husband yelled at the guy to get away, but that kind of thing is really annoying."

Park Service officials said last week that they would not permit souvenir vendors on the Mall during the weekend, but hundreds of vendors ignored the warnings and piled the crowds throughout the day.

One of the biggest losers, according to its promoters, was a full-color poster of the pope, which carried on the back side a single page of a newspaper called The Washington Tribune.

Charles R. Wright, president of Acton Publishers, Inc., of McLean, Va., said his company sank $150,000 into the poster promotion. More than 1,000 hawkers responded to ads that proclained: "Earn over $1,000 in Two Days."

But by the end of the mass yesterday, Wright said he had sold about 39,000 of the 300,000 posters printed, and all but 196 of the 529 vendors he signed up had deserted him.

Wright's venture was complicated further when he discovered that the newspaper name (Tribune) he created for his promotion belonged to a neighborhood newspaper published in Washington by Donald Smith, an editor at Congressional Quarterly.

After Wright received an angry call from Smith, there was a meeting during which Smith said he inspected the editorial integrity of the text on the back of the poster and accepted $1,000 from Wright for the use of the name.

"There's no question we took a beating," said Wright, "Quite frankly, we have a pile of posters."

The intensity of the competition among souvenir vendors appeared to take its toil on many of the young people who signed up hoping to both pick up spending money and get close to the papal mass.

One moment after Elsa Levy shouted to passersby, "Pope medallions, remember the pope in gold,' she turned to a reporter and said, "God, I hate to do this. I'm so embarrassed."

Food vendors reported a brisk business throughout the day despite the relatively small crowd.

"I have only one hot dog left," said one weary vendor to the long line of people outside her window. "The rest of you are just going to have to pray until you get home."