This report is a summary of the joint activities carried out by a number of departments of the Government of Thailand, UNEP - ROAP and GRID. The project was devoted to an analysis of deforestation and associated environmental hazards in Chiang Mai Province in Northern Thailand. The basic objective was to demonstrate the potential of computer-based GIS technology for resource management and environmental planning. The study was focused on two issues, namely: Assessment of deforestation in Chiang Mai Province between 1975 to 1985. Assessment of soil-loss in Mae Kiang watershed. The magnitude and rate of deforestation in Chiang Mai Province was assessed using Landsat MSS data for the years 1975, 1979 and 1985. The study revealed that the rate of deforestation between the period 1975-79 was more than that during 1979-1985. The plausible explanation for this is that during the 1970's the Government of Thailand tried to boost agricultural production which, among other things, necessitated clearance of more forest areas for expansion of agriculture. The soil-loss analysis for Mae Kiang watershed was conducted using the Universal Soil Loss Equation (USLE). The results indicated that soil erosion was minimum in paddy fields of lowland areas and densely forested areas at higher altitudes which were covered with thick litter and undergrowth.