Goal-directed exploration, as an indicator of mastery motivation, may provide an important avenue of study to enhance learning by children with cognitive delays. Strategies to assess a child's use of mastery behaviors, however, have been based primarily on research conducted with nondelayed infants. It has been suggested that these assessment techniques may not be appropriate for children with cognitive delays, given their inclination to perseverate and to be motivated by easy rather than moderately challenging tasks. The purpose of this study was to investigate the basis of behaviors that may reflect mastery motivation with a group of young children with moderate and severe cognitive delays. The results supported the application of the mastery motivation model to this group of children. The children used mastery behaviors significantly more often than lower-level exploratory behaviors. The use of mastery behaviors was related to the occurrence of success, and there was a greater-than-chance likelihood that success would follow the use of mastery behaviors. These findings support, the continued investigation of the use of mastery behaviors as a vehicle of learning by young children with cognitive delays.