Pompeo was due to meet Merkel and German Foreign Minister Heiko Maas in Berlin but State Department spokesman Morgon Ortagus said the talks needed to be rescheduled due to "pressing issues," without elaborating further.
"We look forward to rescheduling this important set of meetings," Ortagus said in a statement. "The secretary looks forward to being in Berlin soon."
Merkel's office confirmed the cancellation "by the American side" but referred other questions to the U.S. Embassy, which had no further comment.
Maas said he had talked with Pompeo by telephone, and they had agreed to find another time for a meeting soon.
Pompeo has been taking part in a meeting of the Arctic Council in Finland. It wasn't immediately clear where he would be heading next.