This is the fifth time that the Kyrgyz parliament has rejected the treaty, which has already been endorsed by Kazakh lawmakers.
Critics say the pact in its present form fails to address a number of issues, including migration, water resources, and the transit of goods through Kazakhstan.
Kyrgyz lawmakers also rejected a treaty delineating the country's border with Kazakhstan. That treaty too has already been ratified by the Kazakh parliament.
Lawmaker Murat Zhuraev, who voted against the treaty, said the treaty would give Kazakhstan "strategic spots," while Kyrgyzstan would only receive "useless lands" in return.
Another critic, opposition lawmaker Omurbek Tekebaev, called upon the government to open new talks with Kazakhstan about the border.
(24.kg, AKIpress, Kabar)