Research aim: Impairment of nonverbal communication in persons with autism spectrum disorders (ASD) is a specific and dominant symptom of this disorder's clinical picture. It becomes a diagnostic criterion as well as differential diagnostic criterion. It predicts its development, and at the same time, is a striking determinant of socialization of persons with a given impairment. The range of impairments for this form of communication is variable, and manifested differently in each individual with ASD. Our paper will primarily focus on the area of non-verbal communication, associated with deficits, and related to the reception and expression of facial expressions. The theoretical basis - the initial part of the given paper, will subsequently be supplemented with research investigation, carried out at the Institute of Special Education Studies at the Faculty of Education, Palacky University in Olomouc (Communication deficits in selected forms of impaired communication ability, with focus on assessment of sub-determinants of verbal and nonverbal element of communication in special education practice; Faculty of Education UP, PdF_2012_021, 2013/2014). Objectives: The given research investigation is differentiated into two parts focused on the reflection of impaired nonverbal communication in persons with ASD from the perspective of speech and language therapists, working in health-care and education facilities, and on the analysis of impaired nonverbal communication in a selected group of pre-school aged children with ASD. Methodology: The first research method was a questionnaire distributed to speech and language therapists working in the health-care facilities and in the set-up of Ministry of Education, Youth and Sports. Another research method was longitudinal observation within the time period March 2013 to June 2013. In order to assess nonverbal communication in persons with autism spectrum disorders, Diagnosis of impaired communication ability was applied - specifically its part Diagnosis of nonverbal communication, created by Rihova and Vitaskova (2012). Results and conclusions: It is clear from the results of research investigation that impairment of nonverbal communication in persons with ASD is a very evident symptom, while difference in the extent of impairment of individual forms of nonverbal communication are specific. They reflect individual abilities and dispositions of a child, as well as especially the specific type of ASD diagnosis. If we look at the specific results, acquired from questionnaires distributed to speech and language therapists in the Czech Republic, it is evident that in persons with ASD, the addressed specialists most frequently record deficits pertaining to visual contact and facial expressions. What we perceive as negative is a fact that 55.56 % of speech and language therapists do not prefer the development of nonverbal communication as part of speech and language intervention in persons with ASD. The presented results could be an incentive to reflect the over significance of deeper diagnosis of impaired nonverbal communication in persons with ASD, which can not only form an important diagnostic tool, but also a significant intra-phenomenon differentially diagnostic marker.