A large sample of marine sediment was ground to diameters less than 62 mu and divided into 17 sub-samples. Five of these sub-samples were shaken in distilled water, centrifuged, and filtered to determine the losses incurred by this process of desalting. The remaining 12 sub-samples were similarly desalted and each subjected to 10 initial aliquot measurements to determine how precisely the initial aliquot measured the quantity of fines being pipetted. Concurrent with this, 14 Recent marine sediments were filtered after pipetting was completed. The quantity of recovered sediment was statistically compared to the assumed or previously determined concentrations. These data were used for the statistical evaluation of 3 different estimates commonly used to determine fine fractions, These are: a) assumed fine fraction (weight of fines before desalting), b) corrected fine fraction (weight of fines after desalting), c) initial aliquot (weight of fines indirectly determined by pipetting the suspension). Desalting losses were found to be significant for the sediment used, making the assumed fine fraction weight in error by the quantity lost. The corrected fine fraction technique accurately measures the fines, but this technique is slightly more difficult than the others. The initial aliquot was found to measure the quantity of fine fraction in the cylinder adequately. Since this method requires no drying of the sediment, complete dispersion is more readily assured.