This study examined production of the modal and vocal fry registers using various acoustic and aerodynamic parameters. Airflow (AF), air pressure (AP), electroglottalgraphic (EGG), and acoustic data were obtained simultaneously for four isolated vowels (/i/, /(ae ligature)/, /a/, /u/) and the stop consonant produced in a string of /pi/ syllables for both modal and vocal fry registers. Twenty normal speakers (10 males, 10 females) who were able to produce vocal fry participated in this study. Results demonstrated considerable differences among AF, AP, EGG, and acoustic signals for the modal and vocal fry registers. The fundamental frequency in vocal fry register (male: 49.1 Hz; female: 48.1 Hz) was found to be significantly lower than that in modal register (male: 117.5 Hz; female: 211.0 Hz). Also, the average air pressure values decreased in vocal fry register (male: 5.51 H[inf 2]O; female: 5.25 H[inf 2]O) compared to values obtained in the modal register (male: 7.45 H[inf 2]O; female: 7.56 H[inf 2]O). In vowel production, the airflow rate in the modal register was almost three times as high as the airflow rate in vocal fry register. For the production of /pi/, airflow rate associated with the stop consonant in the modal register was approximately 1.5 times higher than that in the vocal fry register.