Description of ADAPLAB-3 (MATLAB ToolBox) for finite-frequency identification and adaptation is given. As distinct from known MATLAB ToolBoxes, ADAPLAB-3 algoritms proceed from assumption that an external disturbance applied to a plant and a measurement noise are unknown but bounded functions. A test signal as a sum of a minimal number of harmonics is used for identification. An adaptive control is formed on the base of H-infinity optimization and the results of identification of the plant and a closed-loop system. ADAPLAB-3 has some substantial differences from the early developed toolbox ADAPLAB-M: the discrete-time plants are considered the amplitudes and the frequencies of the test signal are tuned automatically during the identification and adaptation process the time of identification and adaptation is determined automatically in dependence on the current external disturbances and the noise.