Pamuk goes on trial in December for "insulting and weakening Turkish identity" after talking about the massacre, a taboo in Turkey.
He also said Turkish forces were partly to blame for the deaths of more than 30,000 Kurds in the 1980s and 90s.
"I repeat, I said loud and clear that 1 million Armenians and 30,000 Kurds were killed in Turkey, and I stand by that," Pamuk said in Frankfurt, where he is due to receive a major literary award on Sunday.
Turkey's most prominent writer said he had not used the word "genocide" to describe the mass killings of Armenians in 1915.
"Whether it should be called genocide or mass murder ... or something else, has to be decided by experts," he said.
Turkey rejects charges
Turkey, home to about 60,000 ethnic Armenians, rejects the charge of genocide and says both Christian Armenians and Muslim Turks suffered mass killings in a conflict during the second world war.
Armenian-Turkish journalist Hrant Dink received a six-month suspended prison sentence earlier this month for insulting Turkish identity in an article.
Turkey hopes to join the EU and
entry talks are under way
Turkey's foreign minister has said he expects the charge against Pamuk to be dismissed.
The issue of freedom of speech has dogged Turkey's efforts to join the European Union.
Entry talks between the EU and the largely Muslim country began earlier this month after lengthy wrangling among the EU's 25 member states on conditions.
Pamuk, whose novels including My Name is Red and Snow have been translated into dozens of languages, said he supported Turkey's bid to join the EU.
"I wish with all my heart that Turkey will become a member of the EU but this is totally a political issue, not a cultural one," he said.
Pamuk is to receive a German
book association's peace prize
"The entry of Turkey into the EU will also enrich the EU's culture."
Germany's chancellor-designate Angela Merkel is one of a handful of EU leaders to oppose full membership for Turkey, and opinion polls indicate high levels of opposition to the move among citizens of Germany, home to almost 3 million Turks.
Pamuk, 53, is the second Turkish author to receive the Peace Prize of Germany's book trade association, Germany's highest literary honour, in its 55-year history.
Yasar Kemal was awarded the prize in 1997.
Pamuk, whose writing is often lauded for straddling Europe and Asia - as does his home city of Istanbul - named the great European novelists as his biggest influences.
"Dostoyevsky, Thomas Mann, Tolstoy, Proust, Joyce, Virginia Woolf, Faulkner ... all these had a great influence on me, and when I write I speak with them," he said.
"I repeat, I said loud and clear that 1 million Armenians and 30,000 Kurds were killed in Turkey, and I stand by that"
"European writers have helped their countries develop and I count myself among them."
Pamuk said he had never sought political controversy.
"I am a Turk. I've lived in Turkey for 43 years, and for that reason my political observations are about Turkey, because that's what I know," he said.
"I never asked for a political role ... it just happened to me," he said. "Nonetheless, I accept the responsibility gladly."