Business at Nuby Hurtado’s small “multi-service” company in Queens is booming this tax season with illegal immigrants eager to get in good with the American government.

As the Senate considered immigration reform in recent weeks, the most rapt audience likely has been the nation’s estimated 12 million illegal immigrants. A key detail they have latched onto is how to qualify for citizenship through the programs under consideration. While the competing legalization proposals differ, one thing they have in common is that illegal immigrants would have to prove they paid their taxes.

As a result, area tax providers are reporting a rush of immigrants seeking their services. Ms. Hurtado said she has seen a 30% increase in business versus last year. At FoodChange’s Jackson Heights branch, which provides free tax-filing services, the site manager, Oscar Quinonez, said his business has more than doubled. The director of the Emerald Irish Immigration Center, Siobhan Dennehy, said, “We’ve never had the same interest in this topic before.”

The idea of illegal immigrants paying taxes is not new, however. Despite popular perception, the majority of America’s illegal immigrants are believed to do so.

Many purchase fake Social Security numbers and green cards for less than $100 in Jackson Heights and other immigrant neighborhoods and then pay into the system. They do not receive a return, however: About $7 billion a year in undocumented taxes pours into the Social Security Administration.

Others use the Individual Taxpayer Identification Numbers created in 1996 as a solution to the flood of taxes filed under false Social Security numbers. In the past decade, the Social Security Administration has issued more than 10 million of these numbers.

With immigration reform pending, the tide has been shifting and even more illegal immigrants are joining the ranks of America’s taxpayers.

Although immediate immigration reform appears unlikely, they are wise to do so. Paying back taxes is required for any adjustment to legal status and will be a prerequisite if any immigration reform plan goes forward. Senator McCain, a Republican of Arizona who is a key proponent of immigration reform, issued a statement yesterday vowing that the Senate would again take up a stalled immigration reform plan when it returns after its Easter recess. The public, he said, wants an “earned path to citizenship for the millions of undocumented immigrants who work here that substitutes fines, civic responsibilities such as paying back taxes and learning English, and a place at the back of the line for the de facto amnesty that exists under our current system.”

Even if the reports that the immigration reform effort has failed are true, Mr. McCain’s statement feeds the hopes of immigrants. “They want to pay their taxes in case, God willing, there is an immigration reform. They can show they were doing something legally,” Mr. Quinonez said.

To some preparers, serving as an immigration adviser as well as tax preparer can be a frustrating experience. “They don’t want to pay taxes: They want to prepare for their immigration interview,” the manager of the Astoria branch of Liberty Tax Service, Abdel Soliman, said. Most of his clientele are self-employed either as babysitters or street vendors, he said, and they think paying taxes “will help their legal status.”

Armando, a 22-year-old deliveryman from Mexico, sought Ms. Hurtado’s help after watching a report on Spanish-language television that said paying taxes could help his bid for legal status. Since he stole across the Mexican border at 15, he has worked illegally in New York for seven years but never paid taxes. Yesterday afternoon, however, while his young wife cradled their 2-year-old U.S. citizen daughter, he reviewed his first tax form – reporting a little more than $5,000 from the Murray Hill deli where he works part-time – and then signed his name.