The differential diagnosis of conversion speech disorders and dysarthria is difficult, and publications on the topic are scarce. This study describes the case of a 47-year-old woman with conversion disorders mimicking post-stroke dysarthria. A speechlanguage pathologist analysed the record of the woman’s speech. In speech-language diagnosis, (1) tongue and lips nonverbal movements, (2) reflexes, (3) muscle strength (preliminary clinical assessment), (4) maximum phonation time, (5) diadochokinesis (tongue tests), and (6) articulation were assessed. After the examination based on the Polish version of the Frenchay Aphasia Screening Test, aphasia was excluded. Examination results showed great variability in observed symptoms involving the non-verbal and verbal motor skills, which were inconsistent with the patient’s general medical condition. The psychological diagnosis turned out to be insufficient for the patient with conversion speech disorder. Based on this case, the authors underline the need for interdisciplinary cooperation between speech-language pathologist and psychologist in the diagnosis of conversion speech disorders.