On Sunday a court in Ankara dropped charges against Pamuk on a technicality. He faced a prison sentence for "denigrating the Turkish national identity" in published remarks about the mass killings of Armenians and Kurds during World War I.
The case had raised questions about freedom of speech in Turkey and Ankara's hopes to join the EU -- a process Rehn is overseeing.
"This is obviously good news for Mr Pamuk, but it's also good news for freedom of expression in Turkey," Rehn said in a statement. He expressed the hope that the dismissal of Pamuk's case would help other intellectuals facing persecution in Turkey.
"Several journalists, editors, writers and academics still face similar charges today," he said. "I hope therefore that the decision on Orhan Pamuk's case will pave the way for a positive outcome for them as well, so that freedom of expression for all Turkish citizens is fully respected."
In October, Rehn met with Pamuk at his home in Istanbul in a show of support for the writer. That visit came a week after Turkey formally began EU membership negotiations.