This study investigated the prevalence and type of gastrointestinal (GI) and food selectivity (FS) symptoms in 163 preschoolers with ASD, and their possible links with core ASD features and emotional/behavioural problems. 40.5% of children with ASD had at least one severe GI symptom or FS. Preschoolers with and without GI symptoms and with and without FS were significantly different on several emotional/behavioural problems and restrictive/repetitive behaviours, whereas they did not differ significantly on performance IQ and autistic severity. The GI plus FS group presented with Sleep Problems, Self-injurious Behaviors and Anxiety Problems. Results indicated the need for early identification of GI disturbances and FS in order to design tailored intervention for these symptoms frequently associated to challenging behaviours in ASD.