Santa didn't wait for nightfall to bring a sack of toys to the house on North 22d Street yesterday. Old St. Nick and three elves in sweatpants took some teasing from the neighbors for making their grand entrance through the front door instead of the chimney.

But for four children, 9 months to 11 years, who stood on the other side of that door, the details were secondary: Santa had brought presents in a year when presents have been few.

"Ho, ho, ho! Merry Christmas!" Michael DeFeo, 17, a junior at St. Joseph's Preparatory School, bellowed as he reached the door. A grandmother named Theresa, who lost her job in April, cheered and invited DeFeo and his three classmates into her tidy home.

DeFeo and his crew were but one platoon in an army of more than 600 teenagers who fanned out across Philadelphia yesterday to deliver gifts to needy families, part of a program run by the Archdiocese of Philadelphia. Church officials said teenage elves and Santas visited as many as 800 families, delivering more than 20,000 toys.

The program wasn't even a program when it began 42 years ago. It was a few teen boys who decided to deliver gifts to neighborhood families they knew were in need, said Tricia Cellucci, a volunteer. Nowadays, parents do the driving, but it's still the teenagers who sign up, dress up, and hand out gifts.

"For a teenager to give up their Christmas Eve is pretty remarkable," Cellucci said.

Yesterday, the young Santas and elves picked up their toys and costumes at three spots, including St. Joseph's Prep. By 1 p.m. a line stretched out the door.

In a gymnasium, teens grabbed large black trash bags stuffed so full of toys that box edges ripped the plastic. Girls giggled as they donned saggy red pants and elf caps.

Maura Angiolillo, 14, of Glenside, suffered a wardrobe malfunction as she left the school: Her Santa pants slipped down to her ankles. Her four elf helpers, all freshmen from St. Basil Academy in Jenkintown, howled with laughter as she retied her trousers.

"My pants are a little big," she said.

This was the St. Basil group's first time delivering gifts. They memorized the names of the children getting the gifts and planned to sing a carol at each of four homes on their list.

"It's, like, sad, thinking about how you get, like, 20 gifts every Christmas and they get, like, one or two," said Coeli Turncach, 14, of Huntingdon Valley.

DeFeo, of West Chester, strove for authenticity in his Claus look. A running back on the Prep's football team, he didn't have enough of a jelly belly, so he stuffed his corduroy Santa jacket with a friend's sweatshirt.

DeFeo and his crew, too, were making the rounds for the first time. All juniors at St. Joseph's, they piled into a blue-gray van and headed north across the city.

"All right, this is it!" a chaperoning father shouted as they reached their first stop. A Prep boy shouted back, "This is big!" Another: "Go! go! go!"

The family at that stop wasn't home, but neighbors greeted them warmly. DeFeo, his face swathed in cottony beard, affected a deep voice and shouted, "Ho, ho, ho!"

"Oh, hello, Santa!" replied Lily Nash, a neighbor whose 3-year-old niece, Nicole, was mesmerized by the costumed visitors. "Oh, this is so nice!"

Back inside the van, Mark Casale, 17, of Radnor, teased DeFeo about his Santa act. "I wasn't expecting you to be so enthusiastic," he said.

The next stop was home to Theresa and her grandchildren. A teacher's aide, she lost her job when the center where she worked closed. Two of her grandchildren are in the Early Headstart Program, which teams with the archdiocese to bring gifts to lower-income families during the holidays.

Charles Foltz, 17, of Wynnewood, handed a candy cane to 9-month-old Joslyn, who stared up at the boys. Sean Mack gave a present to Rashid, 11, who nodded bashfully.

"There's someone here to see you all," Theresa said as the other two children, Josiah, 3, and Phoebe, 5, came through the door.

Casale handed Josiah a bag of Wiffle balls. Out of the packaging popped a plastic bat. The elves gave Phoebe two boxes wrapped in silver. Phoebe smiled.

"We thank you all, truly," Theresa said as the Prep boys turned to leave. "It's a blessing."

Later in the afternoon, many of the volunteers joined nearly 800 worshipers at a Christmas Mass in a ballroom in Drexel Hill. Tom Mitchell, 16, of Newtown Square, was still in his Santa suit when he trundled in, fairly beaming.

"The first house we went to didn't even have a Christmas tree," said Mitchell, a junior at Archbishop Carroll High School in Radnor. "And it was just great, dropping off toys and watching their faces light up as they got it."

Auxiliary Bishop Joseph P. McFadden reminded the throngs of Santas, elves, and parents about the meaning of the day's giving, and of the holiday that awaited.

"You have done what Jesus intended to do when he himself came into the world," McFadden said in his homily. "Because, you see, Jesus did not come in a huge mansion. . . . He came to be with the poor."