Art Cashin told CNBC on Friday he hopes the doesn't struggle to stay above the 20,000 level like it did at 10,000.
Traders are watching on Friday to see if the Dow can hit 20,000 for the first time. On Thursday, the Dow closed about 60 points higher, within 200 points of that milestone.
But Cashin, UBS director of floor operations at the New York Stock Exchange, said people should calm down a bit. When the Dow hit 10,000 in 1999, it seesawed for quite a while, he said.
"In fact, Dow 10,000 was such a struggle that we crossed that line 67 times before we finally got above it and stayed above it," Cashin said on "Squawk on the Street".
Cashin also said the rally after Donald Trump's election victory is still good for investors who want in.
"I'm of the mind that I think the post-election rally will modify somewhat, but I don't think the correction we'll see go straight down because of all those people who want to buy the dip," he said. "You know, the market got away from me, but if I could only get a small sell-off, I'll get myself back in."