Huntington’s disease is a hereditary neurodegenerative disorder, which is associated with movement disorders, psychiatric findings and dementia. Underlying cause is a mutation of Huntington gene, which is located on short arm of Chromosome 4. The mutation leads to expansion of CAG trinucleotide repeat. Onset is usually around 4th decade of life and usually, patient is presented with motor coordination problems. Parkinsonism is found in almost all the patients. Cognitive findings may precede movement disorders. Cognitive impairment aggravates and clinical picture of dementia becomes remarkable as the disease progresses. This report will address a patient with Huntington’s disease, which was associated with depression and frontal dysfunction at baseline, progressed into dementia with movement disorders added into the clinical picture at advanced stage. The thirty nine years old female patient was admitted to our outpatient clinic due to complaints of loss of motivation, malaise, inability to do daily activities, tendency to sleep continuously, short temper and aggressive behaviors associated with onset of bad temper. It was understood that complaints started 10 years ago, patient had treatment based on diagnosis of depression and patient had no benefit from treatment. It was also understood that complaints aggravated within 2 years, patient could carry out no daily work at home, memory impairment progressed, patient was less motivated and patient could not cook. Patient was hospitalized. On psychiatric examination, she had poor self-care. Attention loss was observed. Orientation was intact. Instant and short- and long-term memories were poor. Patient had difficulties on perceiving time şow. Speed and content of speech were poor. Reaction time prolonged. She had short answers to questions. Affection was limited. Thought content was inappropriate. Associations and psychomotor activity decreased. Patient did not have delusion, hallucination and illusion. Abstract thinking, calculation and knowledge were not sufficient. Sleep quality was poor. Speed of movements was remarkably slow. Patient was lurching and repetitive hand and lip movements were observed. Medical history was obtained from family and it was understood that involuntary movements have been persisting for 2 years and frequency gradually increased. Patient had difficulty in understanding instructions and had no interpersonal communication. It was observed that the currently used antidepressant offered no benefit. Familial history indicated that speech and movement disorders, behavior changes and involuntary movements had been observed in grandfather, father and aunt, resulting with bedridden life and death. Patient had 22 points in Mini Mental test. Cranial MRI resulted with non-specific changes. Patient was consulted to neurology department due to poor frontal functions and involuntary movements and Huntington’s disease and dementia secondary to former one were considered. Trinucleotide repeat was 16/44 in Huntington gene, which is located on Chromosome 4, as indicated by DNA fragment analysis. Based on current clinical history, familial history and genetic analysis, diagnosis of “Huntington’s disease and dementia secondary to Huntington disease” was confirmed. Donepezil and tetrabenazine were added onto current antidepressant therapy. Calmness slightly regressed during follow-up. Patient started to achieve simple daily activities at home. A very slight improvement was noted in involuntary movements.