In one of the largest telecommunications deals in years, CenturyTel, a provider of local phone and Internet services, said Thursday that it would acquire Qwest Communications in a $10.6 billion stock swap.

Both companies, which have large landline operations, have sought to increase their businesses in the shadow of bigger competitors like AT&T and Verizon Communications, which offer both landline and cell phone services. The telecommunications industry has been ripe for further consolidation, which might resemble the wave of deals that swept the sector in the 1990s, analysts said.

The combined company will serve local markets in 37 states with about 5 million broadband customers, 17 million wire lines and 850,000 wireless consumers, the companies said in a statement.

The merger is also indicative of the broader struggles facing phone companies that are dependent on revenue from customers with landline phones, said Craig Moffett, an analyst with Bernstein Research. More consumers are disconnecting their home phone lines in favor of their cell phones or Internet telephone service. “This is a business that is in inexorable secular decline,” he said. “The wire-line phone companies are doing their best to find synergies to preserve the economics of their business.”

Philip Cusick, an analyst at Macquarie Research, said: “All the wire-line telecom companies understand their business is shrinking. The wireless industry is not a growth space either. This roll-up attitude could continue for a few more years.”

Indeed, AT&T said Wednesday that it only added 512,000 wireless customers under contract, also known as postpaid subscribers, during the first quarter — down 43 percent from a year ago. Verizon Wireless said Thursday that it added only 423,000 customers under contract during the first quarter, down 55 percent from the same period a year earlier.

Combining with Qwest would make CenturyTel the third-largest supplier of landline phone lines, trailing AT&T, which has 46.5 million wire-line subscribers and Verizon Wireless, which has 32.6 million wire-line subscribers.

But that number is expected to continue to contract, especially as consumers increasingly rely on cable companies for home phone service, said Roger Entner, an analyst with Nielsen Mobile.