There was a time, not long ago, when Peter Capolino wouldn't have known Ja Rule from Bob Rule and, frankly, could not have cared less. Capolino owns Mitchell & Ness, a sporting goods store in Center City Philadelphia that his father, Sisto, bought from Messrs. Mitchell and Ness in 1952.

"I've been working here since I can remember," says the pale, bespectacled 57-year-old Capolino, dancing around open boxes of material and order forms on the third floor of his cramped 19th-century building. "My father outfitted the Phillies, the Flyers, you name it."

Bob Rule, who played for the Philadelphia 76ers for a short time in the early 1970s, may well have worn Mitchell & Ness gear. But it is certain that Ja Rule, the rap artist, is well-attuned to Mitchell & Ness. In Ja Rule's video for "Thug Lovin'," for instance, there are several players wearing sports uniform shirts, including a rare Boston Celtics Len Bias replica -- Bias having died in 1986 the day after being drafted by the NBA Celtics.

Young music artists, ballplayers and urban hotshots have been flocking to Mitchell & Ness because the small company holds licenses from the four major professional sports -- the NBA, Major League Baseball, the National Football League and the National Hockey League -- to make authentic replica uniforms of retired players. LeBron James, arguably the best high school basketball player in the country, got in trouble recently after receiving two Mitchell & Ness jerseys for free from a store owner.

Capolino started by making about 100 replicas of baseball greats like Robin Roberts and Mickey Mantle in the mid-1980s -- a good little side business at a couple hundred dollars a pop. "I figured my market was 35- to 75-year-old, conservative, college-educated, suburban white men. Somebody like me," he says. He grew the replica business to be his main business, and then his only business by the late 1990s.

Then in 1998, the hip-hop group OutKast appeared on a video wearing Mitchell & Ness replicas of pitcher Nolan Ryan's Houston Astros jerseys and things just exploded. Mitchell & Ness had acquired street cred. A laundry list of the hippest of hip-hop started calling.

"Jay-Z, Jermaine Dupri, Fabolous, Fat Joe, Faith Evans, Freeway, Eve, Bone Thugs-N-Harmony, [Lil'] Bow Wow . . ." Capolino ticks off the names. "Sean Combs, or P. Diddy, has to have the latest. He's calling here all the time."

Jay-Z, in his "Girls, Girls, Girls" video, wears a Mitchell & Ness 1947 Washington Redskins jersey. On "The Blueprint," he rhymes about "the throwback jersey." Fabolous likes the Mitchell & Ness line of defunct teams, like the Virginia Squires of the old American Basketball Association or the Houston Colt .45s, predecessors to today's Major League Baseball Astros. Shaquille O'Neal of the Los Angeles Lakers has an Allen Iverson rookie 76ers uniform shirt, with a design that's no longer in use.

Especially after rockers and ballplayers descended on Philadelphia for the National Basketball Association All-Star Game last February, things burgeoned for Mitchell & Ness. Sales in the small store and through distributors grew five-fold, to $25 million in 2002 (each shirt, warm-up or jacket costs between $250 and $550).

"I don't think I am selling fashion here," he says. "I look at it as selling history. I now get resentful when I hear people saying that the young, urban crowd doesn't know history. These guys come in here and want to get a shirt from their old heroes from a few years back, but also of Wilt Chamberlain and Julius Erving and even George Mikan, who is an old white guy."

Right now, Jim Brown's Cleveland Browns uniforms are selling well. So are the Alex English Denver Nuggets jerseys from the 1980s, with lots of color in the jagged mountain logo. For the NBA All-Star Game in Atlanta tonight, Mitchell & Ness is loading up on old Atlanta Hawks Pete Maravich jerseys, with lots of green and blue.

"Pete is a cult figure," Capolino says of the late Maravich, whose scoring ability and floppy socks brought him legions of fans. "And we know people will be wanting something from Atlanta for the event."

Capolino credits two fortuitous events for his involvement in this fashion craze. Back in 1986, he came upon a large cache of old flannel in a warehouse in Philadelphia. From that, he decided to make a few replicas of old baseball jerseys he had liked -- the Phillies' Richie Ashburn, the Cardinals' Stan Musial, the Braves' Hank Aaron.

"They cost a lot to make, just to get the right people to stitch them correctly," he says. But they sold for $200 to $300 each. That led him into getting the licenses, gradually, for each of the four leagues, starting with Major League Baseball. Each league gets a percentage of his wholesale sales. He would do research on each uniform before getting it made, making sure it would replicate the old jersey -- stitch for stitch. Sometimes that meant actually finding one in an old collection, either through the Internet or word-of-mouth.

"People who want these things want them right," he says. "They are willing to pay the money, but only if they know they are getting an exact duplicate."

Then in April 2001, Reuben Harley, a 27-year-old who had been a customer at Mitchell & Ness since he was a teenager, approached Capolino.

"He told me he could make us famous. He would get these things to ballplayers and hip-hop stars," says Capolino. "All he wanted was a good car as a bonus. I laughed. But I gave him a shot."

Harley was as good as his word.

"I don't know, I just went out there and sold it. The OutKast video was the key," says Harley, who normally gets to the store about noon, but is often working the clubs and the ballgames and the backstages late. "When the other guys saw that, they wanted to have their own. If there is something new, you can't have Fab or P. Diddy both wearing it. It's work keeping track."

Capolino was as good as his word, too. Harley now drives a Cadillac Escalade and gets a "substantial" salary.

Harley planned to be at this weekend's NBA All-Star Game festivities, which have become an annual party-all-weekend event for the upscale hip-hop crowd. But he says he will not be at the parties.

"I'm going to be in the hotel with a lot of different uniforms," he says. "They've got to know where to find me, so I've got to be there with the stuff. You have to serve your clientele, right?"

Mitchell & Ness owner Peter Capolino on a carpet of his replica major league jerseys.Sam Lozoff, 13, studies a replica of a 1955 Philadelphia Warriors jacket. Jackets can sell for as much as $550.