The Rubinstein-Taybi Syndrome (RSTS) literature is limited about sensory integration, which is a foundational neurological function of the central nervous system that may affect the development of cognitive, social, and motor skills. The aim of this case report was to investigate the effects of Ayres Sensory Integration(& REG;) (ASI) intervention on processing and integrating sensations, motor functions and parental goals of 3-year-old child with RSTS. Analysis of assessment data reviewed before and after treatment. Assessment collected by interview, Sensory Profile (SP), Sensory Processing Measure-Preschool (SPM-P) Home, Peabody Developmental Motor Scales-2 (PDMS-2), Gross Motor Function Measurement-88 (GMFM-88), and Gross Motor Function Classification System (GMFCS). Progress toward goals and objectives was measured with Goal Attainment Scale (GAS). ASI intervention was implemented 3 times per week for 8 weeks. At pre-intervention, SP and SPM-P Home revealed prominent sensory processing and integration difficulties in this case. PDMS-2 scores indicated the child was far behind his peers in fine and gross motor areas. In addition, systematic observations determined that the child's GMFCS level was III. After 8 weeks of ASI intervention significant improvements were found in parent reports of sensory processing in the areas of vestibular, tactile, and oral functioning on the Sensory Profile. Gains in functional motor skills were found on the GMFM-88 and the GMFCS. Consistent with these results, significant gains at or above expected levels of performance were found on GAS goals which reflected the family's main concerns for social participation, feeding, play, and movement. There are limited studies on sensory processing and integration in children with RSTS. This case report identified sensory processing and integration difficulties for the first time in a child with RSTS. Results also provide preliminary support for the positive effects of ASI intervention on sensory processing, functional motor skills, and parental goals of a child with RSTS.