High-frequency properties of toroid cores made of amorphous glass-coated micro-wire are reported in this work. The frequency dependencies of permeability and loss factor in the 0.1-30 MHz range are presented. We studied also the dependence of specific losses on flux density. The real part of effective permeability lies in the range of 150-1000, and the value is nearly constant in a broad frequency range (up to 30 MHz). The imaginary part demonstrates a monotonous increase up to 30 MHz for all samples. Specific losses of micro-wire cores are small in comparison to those of ferrite cores.