The fast mapping skills of language-delayed 5-year-old children were investigated. Children viewed a video presentation in which four kinds of unfamiliar words (object, action, attribute, and affective state) were incorporated into a narrative script. The pre- and postviewing comprehension of the targeted words was measured. The language-delayed children were compared to two groups, one matched for chronological age (CA) and the other matched for mean length of utterance (MLU). Children were randomly assigned to experimental and control conditions. All three groups indicated fast mapping of unfamiliar words, although the language-delayed children scored lower than the MLU-matched group, who in turn scored lower than the CA-matched group. The experimental effects were most pronounced for object and attribute words. The limited fast mapping of the language-delayed group was not accounted for by a restricted general vocabulary nor by a general delay in grammatical development.