The present study aimed at investigating the role of temporal integration of voice onset time (VOT), vowel length and noise in the perception of bi- labial stop consonants. For this purpose, a 9 point continuum of voiced to voiceless sound was constructed in a synthetic speech token and each point along the continuum was associated with long and short vowel separately. The stimuli were presented to 30 normal hearing individuals in quiet and noisy situation. Categorical perception was assessed for the identication of perceptual boundary and the reaction time task. The results revealed that vowel length had signicant eect on perception of bilabial stop voicing only in quiet but not in noisy situations. Thus, it was concluded that temporal integration of VOT and vowel length are important cues in quiet situation, but in the presence of noise, individuals ap-pear to use some other cues to perceive voicing of bilabial stop