Successful performance of a vigilance task in a particular modality can be affected by the allocation of attentional resources to other cognitive processes using same or different modalities. The present study investigated whether loss of hearing affects visual vigilance task performance and also if it's a function of increased task complexity. A sample of 30 adolescents (15 with hearing loss and 15 with normal hearing) were selected by matching them in pairs according to their working memory functioning and other relevant organismic variables. A software program measured the performance on vigilance task with varying task complexity levels. Analysis of the obtained data indicates that the effect of hearing impairment on visual vigilance is moderated by task complexity and that is contingent to attentional resources. Here, deprivation in hearing ability negatively affects functioning of visual vigilance significantly only when the task complexity increases. But no significant differences are observed in hearing and hearing impaired adolescents when the task demanded less attentional resources.