Measurements of H2O2 concentrations have been made at intervals along the full length of the Dome Summit South (DSS) ice core from Law Dome, Antarctica. These results show mean peroxide concentrations of approximately 37 parts per billion by mass over the past 4 kyr and a tendency for concentrations to decrease with age. The rate of H2O2 decay in Antarctic ice appears slower than in Greenland ice and the pattern of measurements suggests an abrupt increase in concentration during the emergence from the last glacial into the Holocene. There is some evidence for a recent increase in H2O2, but the data so far are not conclusive. Detailed examination of the timing of the seasonality in H2O2 and Δ18O shows that peroxide extrema occur very near the solstices. These seasonal curves have been used to derive atmospheric seasonal H2O2 curves based on possible air-snow partitioning models. These show a broad low in atmospheric concentration with a sharp peak which is again very near the summer solstice. ¿ American Geophysical Union 1996