The aim of this study was to examine the temperament characteristics of adults with attention deficit hyperactivity disorder (ADHD) and the relationship between ADHD subtypes and temperament. Additionally, the study aimed to investigate the relationship between childhood ADHD symptoms and temperament. The study included 59 ADHD patients aged between 18 and 60 years and 44 healthy controls. All participants completed the Wender-Utah Rating Scale (WURS) and the Adult Attention Deficit Hyperactivity Disorder Diagnosis and Rating Scale. Temperament characteristics were assessed using the Temperament Evaluation of Memphis, Pisa, Paris, and San Diego-Autoquestionnaire scale (TEMPS-A). The ADHD group had significantly higher scores for cyclothymic, irritable, and anxious temperament compared to the control group (p<0.001). The number of individuals with cyclothymic, irritable, and anxious temperament was also significantly higher in the ADHD group (p=0.007, p=0.018, p=0.029, respectively). Positive correlations were found between cyclothymic and depressive temperament scores and WURS scores (r=0.278, p=0.033; r=0.326, p=0.012, respectively), between hyperthymic temperament scores and hyperactivity scores (r=0.399, p=0.002), and between depressive temperament scores and attention deficit scores (r=0.303, p=0.020). There was no relationship between ADHD subtypes and dominant temperament (p>0.05). The most common dominant temperament in the ADHD group was cyclothymic, irritable, and anxious. The positive correlation between WURS scores and cyclothymic temperament suggests that cyclothymic temperament may be a risk factor for adult ADHD.