Studies were carried out to identify a method of constructing a peatland evaluation map based on forecasting data of land subsidence of arable peatland in northern Japan. Land subsidence in a district here has become a serious problem due to the increase in the area of upland fields converted from paddy fields. First, we estimated the present rate of land subsidence based on the measurement of land elevation and soil survey, and determined the degree of decomposition of peat in marshlands, windbreak forests and arable lands in the Ishikari peatland in northern Japan. Second, we evaluated the sustainability of arable peatland based on data of actual land subsidence and other parameters, and we compiled an evaluation map of Ishikari peatland using geographical information systems (GIS). Soil type, period of land development, present land use and thickness of top-dressed soil were selected as main factors for the evaluation, and scores of elements of each factor were determined. According to the total scores, sustainability of arable peatland was divided into 3 classes. A land evaluation map of Ishikari peatland in terms of land subsidence was compiled using these classes.