Peat swamps in Narathiwat are known to occur during the period of 3,000 to 7,000 yrs. B.P. on old sand bars or mangrove clay which monthly underlain by the stiff clay of the Pleistocene surface. Within the lagoonal systems as formed in accordance with the progradational of the shorelines, these swamps had developed. After infilling of the lagoons began, peat development became accelerated depending upon plant successions. According to pollen analysis, the early succession might have been the herbaceous water loving plants, and then, followed by the mixed swamp forest types including of more than 100 genera of trees, palms, climbers, herbs, ferns, seeds, and reeds. However, it is postulated that most of the peet layers have developed from the later dense vegetation under the water-logged condition which is preferable the rate of organic accumulation to that of the decomposition. As a sequence, most peat contains large quantity of the woody materials which are relatively high in fiber contents. The thickness of peat varies from 40 cm up to 3 m. They are extremely acidic but very low in total bases and irons. Although the CEC values are very high, they are pH dependent and most of them are from the H+ ion of the RCOOH radicals.