The damping characteristics of baffles for suppressing sloshing in processing equipment on floating production systems have been quantified by experiment. The 1.78 m long model vessel was part filled with liquid and subjected to accelerations similar to those experienced on a full scale primary separator at +/-4 degrees pitch motion. Two perforated baffle designs and one solid strip baffle were studied. Damping was quantified in terms of an initial wave height following cessation of imposed motion and a decay modulus. Also, the wave spectra were analysed by FFT to give further information on the periods of key components and their amplitudes. Comparison was made with damping in the same vessel without a baffle. An analytical expression for that latter situation proved to be unsuitable for the relatively severe motion conditions encountered in floating production.