The poll revealed that 54.9% of respondents would vote against joining the military alliance if a referendum were to be held tomorrow, and that 22.3% would back joining NATO.
At the April 2-4 Bucharest NATO summit, the 26-nation alliance refused to admit Georgia and Ukraine to its Membership Action Plan, despite U.S. President George Bush's strong support for the former Soviet states' bids. NATO said however that it would reconsider the countries' respective bids at a later date.
The opinion poll also revealed that most Ukrainians approved of the results of the Bucharest summit, with 52.4% saying it was a "good" outcome, and 27.2% disapproving.
NATO's rejection of Tbilisi and Kiev's bids, which was largely a result of objections from France and Germany, was seen partly as a reaction to a comment made by Russian President Vladimir Putin last year that Moscow may have to retarget nuclear missiles at Ukraine if Kiev joins NATO.
Putin gave a closed-door speech to NATO leaders at the summit focusing on Moscow's opposition to the alliance's expansion into former Soviet territory. Various media reports quoted Putin as saying that Russia would re-claim the Crimea if Ukraine joins NATO.
The Crimea, now an autonomous region within Ukraine, is a predominantly Russian-speaking territory. Since the 1991 breakup of the Soviet Union, the Crimea has unsuccessfully sought independence from Ukraine. A 1994 referendum in the Crimea supported demands for a broader autonomy and closer links with Russia.
However, Russian Foreign Minister Sergey Lavrov subsequently gave assurances that Putin had not sought to undermine the sovereignty of Ukraine.
Nevertheless, asked whether they conceded that should Ukraine join NATO, Russia could raise the issue of who the Crimea belongs to, 40.8% of respondents said yes, and 34.5% said no.
The poll was conducted between April 16-25 and involved 2,000 respondents in 160 cities and villages in Ukraine. The statistical margin of error of the poll is 2.2%.