Different methods have been developed for the prediction and topology of transmembrane segments in protein sequences. CoPreTHiuses the results of the most popular prediction methods (DAS, ISREC, PHD, SOSUI, TmPred, TopPred II) that are freely available throught the Internet, combining them into a joint histogram for each protein. Clearly, the joint prediction algorithm, produces superior quality results than individual prediction schemes. The program is available at http://athina.biol.uoa.gr /CoPreTHi