Question: Does anybody know of a freely available program that converts fasta / nexus / mega / phylip etc. files to the *.rdf files used by the NETWORK program Answer: Seems everybody use dnasp. Its free; http://www.ub.es/dnasp/ I tested it and it works. Import your fasta (or whatever) file to dnasp and the export it to the Roehl format. But even easier. You can use Network as it is if you do it correctly: You do not need to convert a file to the *.rdf format. Just go directly to the "Calculate Network: Network Calculations: Median Joining" menu (if that's the type of analysis you want to perform). That will open a new window. After that, you can go to the "File: Open" menu, which will open a conventional Windows file dialog box. From there, just select the type of file you want to open using the drop-down menu at the bottom of the dialog box. You should see a list of different types of files that can be directly read by the program (including nexus and phylip files). Thanks for all the Answers All the best Carina Carina.Schlebusch@nhls.ac.za