A trademark dispute over who gets to sell Italian cuisine under the name Patsy’s is back in court.

Patsy’s Italian Restaurant on West 56th Street — Frank Sinatra’s favorite — asked a federal judge yesterday to stop a restaurant from opening in Syosset, Long Island. The reason for the request, according to a legal complaint filed in U.S. District Court in Brooklyn, is the “Patsy’s” sign above the new storefront.

If the dispute sounds familiar, it is because Patsy’s on 56th Street, which opened in 1944, guards its name as jealously as it would any family recipe. Earlier this year, it went to court to force a Staten Island restaurant doing business under the name Patsy’s to shut its doors.

Another Patsy’s, a pizzeria on 118th Street, which opened more than a decade before the 56th Street restaurant, feels the same way about its name. The pizzeria filed suit against a Patsy’s in Brooklyn, obliging the Brooklyn Patsy’s to change its name. The restaurant now does business as Grimaldi’s Pizzeria.

The 56th Street Patsy’s is known for its pasta; the 118th Street Patsy’s for its pizza. But the culinary interests of the two have overlapped at times, leading to a lawsuit over which establishment had the right to market marinara sauce under the name.

In light of the past cases, the suit over the Syosset restaurant hardly seems a surprise, though it does suggest that the 56th Street restaurant will guard its name against alleged impostors even beyond the five boroughs.

The latest restaurant to become involved is at Jericho Turnpike, Syosset, according to the complaint. The restaurant was nearly ready to open, judging from the lines it is putting down in the parking lot, a lawyer for the 56th Street Patsy’s, Robert Maldonado, said yesterday.

But any grand opening is likely to be postponed. The judge handling the case, Dora Irizarry of U.S. District Court in Brooklyn, issued a temporary restraining order against the new business yesterday, Mr. Maldonado said.

One businessman behind the Syosset restaurant is no newcomer to the dispute over the Patsy’s trademark. Anthony Banas, a co-owner of the restaurant, was the owner of the Staten Island Patsy’s that was sued this year, according to the complaint.

Mr. Banas could not be reached for comment yesterday. The attorney who represented him in the suit against the Staten Island restaurant, Leslie Ben-Zvi, said he could not comment on the latest lawsuit because he did not know whether he would represent Mr. Banas.

But Mr. Ben-Zvi did suggest why restaurateurs across the city, and beyond, were eager to use the name. “There is obviously great currency in the name Patsy’s,” Mr. Ben-Zvi said, adding that food marketed under the name would “sell itself.”