The aim of our study was to explore possible differences in estimation of odor pleasantness in children with autism spectrum disorders (ASD) compared to controls. Thirty-five patients with Asperger's syndrome and high functioning autism (mean age 10.8 ± 3.6 years; 31 boys) were compared with 35 healthy control subjects (mean age 10.4 ± 2.4 years; 28 boys). Odor pleasantness was assessed on a 5-point scale using the Sniffin' Sticks test (Identification part of the test). Patients with ASD, compared to healthy controls, perceived the smell of cinnamon and pineapple as significantly less pleasant (p < 0.05); at the trend level, the same was true of cloves (p < 0.1). The possibility of olfactory dysfunctions as an autism biomarker is discussed.