"I'm very sorry that that has come to an end, and that I wasn't valuable enough for them to keep me on," the 86-year-old Smith said Tuesday.
Smith said the daily newspaper declined to renew her $125,000 annual contract in a letter that said, "due to economic circumstances, they were the bearer of bad news and so forth."
Col Allan, the paper's editor-in-chief, said: "The Post is grateful to have been able to publish Liz Smith's legendary column for so many years. We wish her the very best for the future."
The Texas native writes a syndicated newspaper column that she said is carried by 70 papers around the country. She also publishes in Daily Variety and in Parade magazine, and is part owner of a Web site. Smith says she's also writing a novel and will never retire.
"I'm busy," she said. "I'm OK. I'm OK for a person who's been let go."
In New York, her column had appeared in Newsday until she left in a contract dispute in 2005. The Post had run her column six days a week, and cut it back to three days a year ago to cut costs, despite Smith's unsuccessful appeal to Rupert Murdoch.
Her last column in the Post will appear on Thursday. She's already written it.
"I just wrote the usual stuff," she said, "and then I said goodbye."