Background and Purpose: Cognitive deficits that are associated with coronavirus disease 2019 (COVID-19) and occur in the acute period are gaining importance. While most studies have focused on the elderly severely affected during acute infection, it remains unclear whether mild to moderate COVID-19 results in cognitive deficits in young patients. This study aims to evaluate the post-infection cognitive functions of young adults with mild to moderate symptoms of COVID-19. Methods: A total of 100 adults with similar age and educational background were included in the study. Half of those had been infected with COVID-19 in the last 60 days (N = 50), and the other half had not (N = 50). Global cognitive skills of the participants were evaluated through Montreal Cognitive Assessment Scale (MoCA) and Clock-Drawing Test; memory functions with Öktem Verbal Memory Processes Test (Ö-VMPT); attention span with Digit Span Test; executive functions with Fluency Tests, Stroop Test, and Trail Making Test; visual perceptual skills with Rey Osterrieth Complex Figure Test (ROCF); and neuropsychiatric status with Neuropsychiatric Inventory (NPI). Evaluations were performed in the experimental group for 21 to 60 days from the onset of the disease, and throughout the study, in the control group. Results: It was found that global cognitive skills, verbal memory, visual memory, executive function, and neuropsychiatric status were affected during COVID-19 (p < 0.05). Conclusion: When the cases were analyzed according to disease severity, no relationship was found between cognitive deficits and disease severity.