After Russian Foreign Minister Sergey Lavrov had presented the treaty and urged lawmakers to accept the region as a part of the Russian Federation, the document was approved on a vote of 443 to 1.
Russia's Federation Council upper house will hold a similar vote Friday, completing ratification of a treaty that was signed by President Vladimir Putin on Tuesday.
Speaking "on behalf" of Putin, Lavrov had told the State Duma that folding Crimea into Russia was needed to protect ethnic Russians there.
"I am certain that passing the document will become a turning point in the destiny of multi-ethnic nations of Crimea and Russia, who are related with close ties of the historical unity," Lavrov said.
"These nations joining in the framework of one state will certainly help grow wealth and prosperity and is in line with Russia's interests."
Russia's moves to annex Crimea have turned a confrontation with Europe and the United States into the biggest crisis in East-West relations since the Cold War.
Approval of the treaty in the State Duma was in no doubt as Russia has stood defiant despite Western leaders denouncing Moscow's actions as a violation of Ukraine's sovereignty and a breach of international law.
European Union leaders are due to meet in Brussels, Belgium, on Thursday to discuss the crisis, with possible further targeted sanctions.
U.S. and EU officials have imposed sanctions on more than two dozen Russian and Crimean officials, and urged Russia to avoid escalating the crisis. Moscow has ignored those calls.
U.S. President Barack Obama on Thursday announced more sanctions on people and one bank in response to Russia's annexation moves, as well as a new executive order that authorizes possible further sanctions on what he called "key sectors" of the Russian economy.
"We want the Ukrainian people to determine their own destiny and have good relations with the United States, Russia, Europe -- anyone they choose," he said in calling for continued diplomatic efforts.
The new U.S. sanctions target 20 officials, including senior Russians and "cronies" who hold significant influence in the Russian system, as well as one bank that holds "significant" resources, a senior U.S. administration official told reporters.
That bank was listed by the U.S. Treasury Department as Bank Rossiya.
The individuals named by the Treasury include major Putin allies, both in the Kremlin and in business. Among them are Putin's chief of staff, Sergei Ivanov; the speaker of the State Duma, Sergey Naryshkin; and financier Yuri Kovalchuk, labeled Putin's personal banker by a senior U.S. administration official.
Russia responded with sanctions against a number of U.S. officials and lawmakers, including speaker of the U.S. House of Representatives John Boehner, Senate Majority leader Harry Reid and Sens. John McCain, Robert Menendez and Mary Landrieu.
Boehner's spokesman, Michael Steel, said the lawmaker was "proud to be included on a list of those willing to stand against Putin's aggression."
The senior U.S. administration official, briefing reporters, said Bank Rossiya is run by Yuri Kovalchuk and is the 17th-largest bank in Russia.
It has $10 billion in assets and handles the accounts of some top government officials, the U.S. official said, adding that the bank has U.S. dollar accounts with institutions in the United States, as well as correspondent accounts in Europe and elsewhere.
British Prime Minister David Cameron told reporters at the EU Heads of State summit there would likely be more asset freezes and travel bans.
Lavrov told lawmakers that sanctions "have never brought any positive results" and that there were no legal grounds for them.
Even as Russia insists its actions are legitimate, Ukraine's parliament said Kiev will never stop fighting for Crimea, even if the country's new leaders have discussed evacuating military personnel from the region.
In a declaration published online, the Kiev parliament said "Crimea was, is and will be part of Ukraine."
"The Ukrainian people will never, under no circumstances, stop fighting for the liberation of Crimea from the occupants, no matter how hard and long it is."
Putin announced the annexation of Crimea after voters in the semi-autonomous territory approved a hastily called weekend referendum on separating from Ukraine.
Kiev officials unveiled new measures against Russia and the "self-proclaimed" authorities in Crimea.
In a televised briefing, Andriy Porubiy, secretary of the national defense and security council, said that if the United Nations designates Crimea a "demilitarized zone," Ukraine was prepared to evacuate its military personnel and family members. Ukraine has facilities ready to accommodate 25,000 evacuees.
A statement on the Ukrainian presidential website said former Presidents Leonid Kravchuk and Leonid Kuchma had asked Turchynov to redeploy soldiers who are still in Crimea to the mainland.
The call was "to protect and save lives of Ukrainian servicemen who bear service in difficult and dangerous conditions in Crimea," the statement said. It said Kravchuk and Kuchma strictly condemned provocations and separatist attempts "in some regions" of the Eastern European country.
Porubiy had also said the measures included a full-scale visa system for Russians.
Speaking in Brussels on Thursday, Prime Minister Arseniy Yatsenyuk said Kiev was in no hurry to impose a visa regime on Russia.
"Such an initiative by Ukraine is most unlikely to be effective in terms of influencing Russia," he said, adding that the measure could negatively affect Ukrainians living in the predominantly Russian-speaking east of the country.
Yatsenyuk is in Brussels to sign the political part of an association agreement with the European Union.
Lavrov said the intention to introduce visa regulations was "surprising and regrettable."
As diplomatic efforts to resolve the crisis continue, U.N. Secretary-General Ban Ki-moon traveled to Russia Thursday, where he met Putin and Lavrov. He will then head to Kiev where he will meet acting Ukrainian President Oleksandr Turchynov and Yatsenyuk on Friday.
Russia's Interfax news agency quoted Ban as saying during a meeting with Putin that he was "deeply concerned" by the situation involving Ukraine and Russia.
Navy chief released
Ukraine's navy commander, detained when supporters of Russia took over the naval headquarters in Crimea, was released, the presidential website said Thursday.
Amid signs the uneasy standoff between pro-Russian and Ukrainian forces could ignite into bloody conflict, about 300 armed men stormed the naval base in Sevastopol on Wednesday. They took away Ukrainian navy chief Sergey Gaiduk.
Turchynov issued a 9 p.m. (3 p.m. ET) deadline for Crimea to release all hostages and stop all provocations. Kiev's new leaders had warned that if all hostages, including Gaiduk, were not released by then, authorities would take action of "technical and technological character," probably meaning turning off utilities.
A statement on the presidential site said Gaiduk and several other hostages had been freed. They were released during the night and on their way to Kiev.
Russian Defense Minister Sergey Shoigu had asked authorities in Crimea to free Gaiduk and allow him safe passage out of the region.
The incident at the navy headquarters comes a day after one member of the Ukrainian military was killed, another wounded and more captured when masked gunmen seized their base near the Crimean regional capital, Simferopol.
After that fatality -- the first Ukrainian military death since the Crimean crisis erupted about three weeks ago -- Ukraine's Defense Ministry authorized its forces to open fire in self-defense.