\begin{abstract} In this study, a method for discourse segmentation is introduced and applied to the Turkish language domain. This method is based on the idea that new segments start when related words do not occur frequently and discourse markers appear at sentence initial position. A high correlation is observed by means of statistical methods among human subjects in segmenting discourse. Decision trees for various combinations of criteria have been constructed by a Machine Learning technique. The features that seem to be important are first mention of a word, tense change, time shift, location shift, discourse markers and Centering Theory transitions. Among these, it is observed that discourse segmentation is consistent with the predictions of both the Centering Theory and the hypothesis that discourse markers segment the text. Other than these, related words are observed to appear more frequently inside a discourse segment than across a discourse segment boundary. This feature is used in the construction of the Automatic Turkish Discourse Segmentation (ATDS) tool together with one of the most important computable features: discourse markers. An important by-product of the project is the semantically related Turkish word network for nouns and verbs. The network is not only important for ATDS but also for other studies since there is no thesaurus or semantically related words database in Turkish. Relations are synonymy, hypernymy, antonymy, meronymy and coordinated words for nouns and synonymy, antonymy, hypernymy, entailment, cause and coordinated words for verbs. Implementation of ATDS consists of two phases: \begin{itemize} \item gathering information about the most important parameters with the help of C4.5. \item developing a Neural Network for automatic segmentation that uses the most successful $4$ combinations of the first phase. \end{itemize} We benchmark our algorithm and compare it with the English discourse segmentation algorithms. \end{abstract}