Many ammonites have similar shell shapes and complex suture patterns (the junction between the shell and chamber walls), which makes distinguishing between species difficult. I have developed a user-friendly computer model to match ammonoid suture patterns at the species level. I have chosen to use Geographic Information Systems (GIS) as my software, because it is easy to use and readily available. The ammonites I chose for this project are from the 89 to 94 million year old family Coilopoceratidae. Members of this family look very similar in shape and in suture patterns, which makes them very hard to identify. Using the GIS computer program, I made a template of each speciesí suture patterns. I tested known and unknown specimens within each template to determine species identification. The suture patterns of known specimens fit in the correct templates and did not fit in other speciesí templates. The suture patterns of unknown specimens fit in one template much better than within others, and I could reliably identify each specimen. Using this GIS method will help paleontologists, geologists, and avocational paleontologists in classifying ammonites.