Objective: Attention deficit hyperactivity disorder (ADHD) is a neuropsychiatric illness and etiopathogenetic studies focus on fronto-striatal circuit. Soft neurologic signs that are used in the investigation of brain function disorders in psychiatric diseases were studied more in childhood ADHD. In the present study, it is aimed to study the neuropsychologic test performances that are sensitive to frontal lobe functions and soft neurologic signs in adult ADHD. Methods: Sixty subjects with ADHD and 60 healthy control subjects aging between 18-60 years were included into the study. Presence of comorbid psychiatric disorder was not investigated in the ADHD group. Neurological examination for soft signs and neuropsychologic tests (Digit span, verbal memory, Stroop task and Wisconsin card sorting test (WCST)) were performed to both groups. Neurological examination for soft signs and neuropsychologic tests of 59 patients and 46 control subjects were regarded as effective and were analyzed statistically. Results: Mean age was 28.93±8.08 years in the ADHD group (59.3% female, 40.7% male) and 32.07±8.11 years in the control group (63.0% female, 37.0% male). Significantly low performance was determined in digit span, verbal memory and Stroop task tests in adult ADHD group according to the control group. No difference was determined in WCST between adult ADHD and control groups. In the neurological examination for soft signs, adult ADHD group had significantly low performance according to the control group in motor coordination and finger-thumb opposition tests. Adult ADHD group had significantly low performance according to the control group in sensory integration and audiovisual integration and extinction tests. Adult ADHD group had low performance according to the control group in memory, synkinesis and gaze impersistence tests in Others tests. Discussion: It is implied that ADHD is common in childhood and its symptoms decrease in adulthood. It is also thought that a functional defect continues in frontal lobe, cerebellum, parietal lobe and/or in fronto-striatal pathways that provide associations between each other and this may affect the prognosis and treatment of the disorder. [Anadolu Psikiyatri Derg 2014; 15(4.000): 318-327]