A new testate amoebae, Awerintzewia minuta sp. n. and two rare species, Difflugia serbica Ogden and Živković, 1983, and Difflugia biconvata Ertl, 1965 were found during a faunistic study of the testate amoebae in two high-mountain lakes in Azerbaijan. The morphology and biometrics of these testate amoebae were described by LM and SEM investigations. The genus Awerintzewia Schouteden, 1906 and two species: Difflugia serbica Ogden and Živković, 1983 and Difflugia biconvata Ertl, 1965 are reported for the fauna of the Caucasus for the first time.