This study investigated the effects of lengthened transitions on the perception of stop consonants. In experiment I, three continua representing the phonetic categories [da] and [ga]containing transitions of 45, 95, or 145 ms were presented to 20 subjects for both labeling and discrimination. Results indicated that although there was a significant change in identification performance from 95 to 145 ms, the shape of the functions, and the locus and slope of the phonetic boundary did not significantly vary across transition lengths. In addition, discrimination of within-category stimulus comparisons was significantly better at the 95-ms transition length than at 45 or 145 ms. In experiment II, the availability of acoustic information was investigated further with the adaptation paradigm. Eight subjects labeled the 45-ms series before and after adaptation with 45-, 95-, and 145-ms [da] stimuli. No effect of transition length was found. These results suggest that the slope and duration of formant transitions seem to contribute minimally to the perception of place of articulation in stop consonants.