Just a week after reporting fourth-quarter earnings,

Verizon

(VZ) - Get Report

CFO Doreen Toben says she will retire by mid-year 2009.

Toben had been Verizon's finance chief since 2002, and a replacement is expected to be named soon.

The move comes amid mixed financial performance under challenging economic conditions and heated competition with cable rivals like

Time Warner Cable

(TWC)

and

Cablevision

(CVC)

. Verizon reported solid wireless results last week, but its core phone line business

eroded more than expected

and its service to businesses suffered a surprising decline.

"I have had the good fortune of working with what I consider to be the best financial team in business today, as well as Verizon's superb senior leadership," Toben said in a press release. "I feel very good about how this company has transformed itself in a few short years to become the industry's premier provider of network-based communications services."

In the same press release, CEO Ivan Seidenberg praised Toben's efforts.

"Doreen's contributions as CFO throughout Verizon's history as a company will make a profound and positive difference for many years to come," Seidenberg said.

Verizon shares remained largely unchanged in post-close trading Thursday.