We compared acquisition of, and preference for, manual signing (MS), picture exchange (PE), and speech-generating devices (SGDs) in four children with autism spectrum disorders (ASD). Intervention was introduced across participants in a non-concurrent multiple-baseline design and acquisition of the three communication modes was compared in an alternating treatments design. Children's preference for using MS, PE or the SGD was also assessed. With intervention, all four participants learned to make specific requests using at least one of the three communication modes. The children also showed a preference for one mode. These results extend previous studies by demonstrating (in four new children with ASD) differential acquisition of, and idiosyncratic preferences for, three commonly used alternative communication modes. The present results further suggest faster acquisition and better maintenance with the preferred mode. We conclude that children's preferences for MS, PE, and SGDs should be considered when designing and implementing augmentative and alternative communication interventions. (Contains 1 table and 2 figures.)