Many fishery biologists and policy makers involved in inland fisheries management and planning are unaware of GIS technology and its potential for fisheries planning and management. The FAO Inland Water Resources and Aquaculture Service (FIRI) has been active for the last 19 years in promoting the use of GIS and remote sensing in fisheries and aquaculture. Promotional activities have been carried out through training, projects, field missions, and oral presentations and publications. However, a manual to use along with GIS software for the fisheries biologists in the field explaining GIS in a way that is understandable to non-GIS users had not been produced until now. This manual was written to overcome this knowledge-gap, it is a "do-it-yourself" manual giving a short introduction to GIS software and its applications in fishery science. The overall objective of this manual is to encourage fishery managers to use this tool (GIS) to foster the sustainable use of natural resources. There are five main sections in the manual: GIS concepts and functions and key tools provided by ArcView 3.x, Geographic coordinate system and map projections, Raster data and analysis, Regression analysis, and Application case studies. All sections are accompanied by exercises that have been designed to illustrate key applications of GIS in inland and marine fisheries management. Also, a custom-designed ArcView grid regression extension is included to show the integration of GIS with surplus production models.