Metallic metamaterials (i.e. periodic structures with typical element size smaller than wavelength of light) gained interest due to unusual optical properties they possess. Since extraordinary transmission effect was reported [1], great deal of studies was provided with metamaterials of different geometries. Effects of negative refractive index, birefringence and dichroism are found. Nature of all this effects is in excitation of surface plasmon-polariton (SPP) waves at a metal-dielectric interface. One of the most studied plasmonic metamaterial is a metal film perforated with periodic array of subwavelength slits. When such structure is illuminated with light polarized perpendicular to the slits, surface plasmon-polaritons are exited on front interface and reemited from the opposite one. The type of this plasmon- polariton modes excited in such gratings strongly depends on the slit width [2]. When slits are large, local SPP modes are excited on each stripe. Their properties are determined mainly by the stripe geometry. In case of narrow slits Bragg SPP mode determines optical response of the structure. The wavelength of resonance excitation of Bragg SPP depends on the structure period. Although optical properties of nanogratings were studied intensively in cases of very large and very narrow slits, the case of intermediate slit widths was not covered. In this work light propagation through nanoslit gratings is studied with variable slit width etched in 30-nmthick gold film on fused silica substrate. Ion beam lithography method was used to perforate metal film. The period of the grating is approximately 750 nm slightly changing with each sample. The slit width is varied from 100 nm to 370 nm. When the slit width is 100 nm, transmission spectra at normal incidence contains peaks which can be related to excitation of Bragg SPP. Two peaks correspond to Bragg SPP modes with electromagnetic field localized above slits or above stripes. Dramatic changes are observed in transmission spectra with the increasing slit width. Peaks associated with Brag SPP are blue-shifted, one of them is broadened, the other one becomes more narrow. Finlay, at large slit width, spectra contains broad dip associated with local SPP excitation on each slit. The experimental data are in good agreement with numerical simulations using finite-difference time-domain (FDTD) method.