The times needed to initiate and terminate voicing in response to series of short segments of 1000 Hz pure-tone auditory signal were studied for stuttering and nonstuttering children. The effects of random reward and nonreward on the phonatory response times also were studied. The experimental group consisted of 20 children, 11 of whom had other speech and/or language problems in addition to stuttering and nine whose only communication disorder was stuttering. The control group consisted of 20 normal-speaking children balanced with the stuttering group for sex and age. Children with speech and/or language problems in addition to stuttering were found to have significantly slower voice initiation and termination times than the normal-speaking children. The children with stuttering as the only speech and/or language problem generally did not differ significantly from the normal-speaking children in phonation times. The data suggest that whereas older stuttering children have longer phonation times than do nonstuttering children, younger stuttering children do not. Voicing times for responses following nonrewarded responses tended to be shorter than those for responses following rewarded responses for both groups.