This paper presents a method of determining the compressional wave attenuation in marine sediment from a short range measurement. The data were collected on a vertical line array at a range of 230 m during the Shallow Water 2006 experiments. The sediment attenuation is extracted from the signal strength ratio of the sea bottom reflection to a sub-bottom reflection at different frequencies from 1.75 to 3.15 kHz. Linear frequency dependence of the attenuation is found from the estimation. The sediment attenuation estimate is lower than the values estimated from the inversions of acoustic field data previously done in the vicinity.