The general purpose of the present study was to determine the effect of incidental teaching on teaching three children with autism spectrum disorders to demand their lost objects verbally. These objects are lost during academic, art and leisure activities. This study also was to determine the effectiveness of incidental teaching on generalization and maintenance of verbal demanding skills. The participants were three boys with autism, between 4-6 years of ages, who were attending to a special education school during weekdays. A multiple probe design across subjects was used to determine the effects of independent variable on dependent variable on at least one subject and replicated same process on two different subjects. Maintenance was assessed with three probe sessions after the intervention sessions. This study, which tests the efficiency of incidental teaching on teaching children with autism spectrum disorders how to demand their lost objects verbally, consists of baseline, collective examination sessions, follow up sessions and generalization sessions. Data collected in the study were analyzed by graphical analysis technique. The result of the study shows that incidental teaching method is effective on teaching verbal demanding skills to children with autism spectrum disorders for finding their lost objects. However, one of the subjects was not able to reach the aimed level at this skill whereas the other subject was able to generalize the learned skills on different areas, materials and people.