The Russian and Kazakh defense ministers signed an agreement in the Kazakh capital on October 16 on bilateral military cooperation to replace a deal that has been in place since 1994.
It is said to cover issues including military education and training, arms and equipment deliveries, participation in bilateral and multilateral drills and exercises.
The Russian Defense Ministry called the agreement "an unprecedented document."
In Nur-Sultan, Russian Defense Minister Sergei Shoigu called Kazakhstan "one of the few states, if not the only state, with which we have such broad military cooperation and such a profound and all-embracing agreement."
Shoigu and Kazakh Defense Minister Nurlan Ermekbaev also signed a cooperation plan between their respective ministries for 2021.
Shoigu also held talks with Kazakh President Qasym-Zhomart Toqaev, at which the Kazakh leader hailed the renewed agreement, his office said.
Kazakhstan, the last of the Soviet republics to declare independence in 1991, is one of Russia's closest allies.
It is a member of the Collective Security Treaty Organization (CSTO), comprising Russia and five other former Soviet republics, and part of the Moscow-led Eurasian Economic Union (EEK).