Secondary compression is important in peat deposits because they exist at high void ratios and exhibit high values of compression index Cc display the highest values of Ca/Cc among geotechnical materials, and primary consolidation is completed in weeks or months in typical field situations. Secondary compression of Middleton peat was investigated by oedometer tests on undisturbed specimens. The observed secondary compression behavior of this bibrous peat with or without surcharging is in accordance with the Ca/Cc concept of compressibility. Near the preconsolidation pressure, the secondary compression index Ca, increases significantly with time. In the compression range Ca decreases only slightly with time and for most practical purposes a constant Ca with time can be used to compute secondary settlement.