A principal components analysis was performed on a set (10) of acoustic, aerodynamic, perceptual and laryngoscopic data obtained from 87 dysphonic patients. Two principal components were clearly identified: the first represents in some way the glottal air leakage, resulting in turbulent noise, particularly obvious in higher spectral frequencies, and giving the perceptual impression of breathiness; the second accounts rather for the degree of aperiodicity in vocal fold oscillation, reflected in jitter measurements and with a perceptual correlate of harshness or roughness. Morphological changes of vocal folds correlate more closely with this second principal component. Among acoustic parameters, harmonics-to-noise ratio in the formant zone and magnitude of the dominant cepstrum peak seem to integrate to some extent the effects of both principal components.