Magnetic properties of bulk sediment samples taken from three cores from the Scotia Sea, Antarctica were determined using a fully-automated variable field translation balance. Fine-grained detrital magnetite is identified as the principal carrier of remanence in these Upper Quaternary sediments which were deposited under the influence of the Antarctic Circumpolar Current. Inferred magnetite grain-size is consistent with published bulk grain-size data for these cores. Pseudo-single domain grains characterize Holocene samples, and larger, multi-domain grains occur in glacial samples from two of the cores, whereas samples from the northernmost core site show dominantly multi-domain behaviour.