This paper deals with the filler phenomenon as a form of speech disfluency. A recorded speech sample in the Croatian language lasting for approximately eight hours has been transcribed, based on a corpus of 101students of technical studies at the Faculty of electrical engineering, mechanical engineering and naval architecture in Split. The distribution of frequent fillers in general and while self-correcting has been analysed, including the existence of statistically significant difference regarding the position of occurrence in the utterance. The speakers use the unphonemic segment hm very frequently, independently of the position of occurrence in the utterance. The filler ovaj is statistically more frequently used within the utterance, helping the speaker overcome the current delay, caused by his search for adequate information. The filler znači has statistically more requently the function of leading the listener into the utterance, giving the speaker the required time to plan the message. The results of this study confirm the view that difficulties in message planning result in production delay. Conequently, the primary function of fillers is to “buy“ additional time for conceptual planning and linguistic encoding. Speakers show no tendency to warn the listener about the upcoming repair.