Mitochondrial disease (MitD) is the most common inborn metabolic disease in adult medical clinic. It represents a heterogenous group of disorder resulting from defective oxidative phosphorylation. Nervous system is frequently the most affected major organ system. The aim of this study is to analyse the clinical features and outcome of neurological presentation in patients with MitD. This was a retrospective review on patients diagnosed with MitD following up in an adult medical department of tertiary hospital in Hong Kong from 2002 to 2018. Details of demographic profile, clinical and laboratory investigation results were reviewed. A total of 26 patients [17 men, median age at diagnosis 27 (7 to 61)] with MitD were identified. Sixteen carried m.3243A>G MT-TL1 mutation (15 MELAS and 1 MIDD). Twenty-one patients had neurological impairment as the initial presentation, and their neurological symptoms included seizure (48%), stroke-like attack (43%), myopathy (24%) and encephalopathy (19%). Among those suffering from stroke-like attacks, their age of first attack ranged from 13y to 54y, 44% had at least one recurrence in lifetime, and majority (70%) had a favourable post-stroke neurological improvement without significant disability (mRS ≤2). Ten patients deceased during the study period, 4 (all with MELAS) of them had sudden unexpected death. Neurological impairment was the most frequent initial presentation in patients with MitD. Majority of patients suffering stroke-like attacks enjoyed a favourable recovery after the event despite a modest rate of recurrence. Nevertheless, a higher than expected rate of sudden death was observed.