The effects of pH, NOM concentration, fractions and the chlorine dose on the formation and speciation of THMs and HAAs were determined in Altinapa Dam water (Konya/Turkey). Water sample was isolated and chlorinated at different TOC levels and pH’s. The isolate was fractioned; THM and HAA species were measured after chlorination. THM increased with increasing pH (6 to 8) whereas a consistent pH tendency could not be inferred from the HAA changes. CF is the dominant THM specie which exerts up to 91% of the total THM. The majority of total HAAs composed of MCAA, DCAA and TCAA. The hydrophobic fraction was the main THM precursor under the studied conditions although their percentage was lower than hydrophilics, whereas, hydrophilic fraction had significant contribution to HAA formation, in contrast to the general tendency for HAA. High correlation (0.97) was calculated between total THMs and HAAs.