The experimental results on the structure of oscillating moderate intensity shock waves, ..delta..p/sub 1//p /SUB o/ less than or equal to 25, in a liquid with gas bubbles are presented. It is shown that for ..delta..p/sub 1//p /SUB o/ less than or equal to 1.4 the leading wave front structure is well described by the nonlinear Boussinesq equation. At high intensities the sharpening and growth of the first shock wave oscillation occur. Experimental data are presented on the propagation velocity of waves and gas bubble dynamics.