Intolerance of uncertainty (IU) is indicated as an important transdiagnostic process variable in a range of anxiety disorders. Anxiety is very common in autistic adults. This study evaluates a manualised treatment programme for autistic adults, which focused on IU. An eight session programme (CUES-A©) was developed and delivered to four autistic adults on an individual basis. A single case experimental design was used to provide a preliminary evaluation of the feasibility, acceptability and preliminary effectiveness of the programme. Data regarding retention, acceptability and feasibility indicate that the participants valued the programme. Analyses of outcome measures indicate that the programme has promise as a treatment option for autistic adults experiencing IU.