Those of us who rely on Macintosh personal computers to do our work generally have not been able to link our computers to GPS units. Neither have Macintosh users been able to easily transfer GPS data, including waypoints, to base maps directly from the GPS unit. Until recently, the lack of readily available software and hardware to use with USGS DRG (Digital Raster Graphics) topographic maps has seriously impeded the ability of many who use the Mac to take full advantage of Garmin GPS devices for field work and in our classes. Newly developed hardware and software available provide Mac users with easy access to GPS. The software is MacGPS Pro. The hardware is readily available and simple to plug in and use for most Macintosh models and many models of Garmin GPS units. With Garmin GPS units using MacGPS Pro, it is now possible to upload and download waypoints and their icons, proximity waypoints, routes, track logs, real-time data, and satellite almanacs. Coordinate transfers generate a map that plots the data that have been transferred to the screen. The data are saved in editable, tab-delimited text files, allowing easy data exchange with spreadsheets, databases and text editors. In addition, it is possible to graphically edit waypoints, add, delete, move, change icons, and change other attributes of the data. It is also possible to combine several waypoint files, convert the map datum and change coordinate formats. The software captures and displays real-time data as well as transferring waypoints to the GPS receiver while viewing real-time data. A major feature of the software is that it is relatively simple to convert a map scanned as a PICT file to a DRG map by entering UTM coordinates for several known locations on the map. The versatility and economical price of the software and hardware (currently about $100) should provide easy access and more widespread use of GPS to a much larger number of Macintosh PC and Garmin GPS users.