In this study, analysis techniques based on chaos theory were used to analyze far-field acoustic pressure waveforms of the fricatives /s/5 ///, /z/, and /$/. Results indicate the presence of low-dimensional chaos in the fricative time-series data. In addition, it was found that phase trajectories of the steady-state parts of the voiced fricatives were distinctly different from those of the voiceless ones; this observation suggests the potential use of phase trajectories as an effective voiced/voiceless classification technique for fricatives.