Asperger syndrome belongs to very serious developmental disorders. The development of an individual with the Asperger syndrome compared to normal development is obvious from early infancy and maladaptive and abnormal behavior occurs during the whole following life of the individual. The diagnostics of Asperger syndrome at the preschool age appears to be easier for occurrence of specific autistic symptoms, whereas manifestations of Asperger syndrome at the school age are not so typical and may be associated with other diagnostic categories especially in cases, where clinical manifestation had not been sought in taking history of the child at the preschool age. The undiagnosed or erroneous diagnosis may result in serious consequences including the effect on decreased quality of life in the affected individual. The communication also includes two case histories demonstrating early and belated diagnostics of the disorder.

        Key words: Asperger syndrome (AS), early diagnostics of AS, maladaptive behavior of individuals with AS, symptomatology of AS, specific interests of AS