Abstract Background There is a need of comprehensive standardized diagnostic assessment tools of psychopathology that match recent changes in diagnostic classification systems, such as the 5th edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5). Therefore, the computer-assisted DIA-X-5 was developed and its test-retest reliability was explored. The DIA-X-5 is based on the DIA-X/M-CIDI (Diagnostisches Expertensystem für psychische Störungen/Munich-Composite International Diagnostic Interview) which referred to the 4th edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV). Methods A convenience sample (N = 60, age: 15–67) was interviewed twice with the computer-assisted DIA-X-5 interview, on average nine days apart, by trained and blinded interviewers. The DIA-X-5 is a standardized instrument for research purposes covering symptoms, syndromes and diagnoses from eleven classes of mental disorders according to the DSM-5 with matching F codes of the 10th edition of the International Classification of Diseases (ICD-10). Results Kappa values ranged from 0.90 for post-traumatic stress disorder to 0.30 for social anxiety disorder. For age of onset and age of recency, test-retest reliability as measured by intra-class correlation was satisfying with values above 0.90 for most disorders. Conclusions Test-retest reliability of the DIA-X-5 syndromes and diagnoses were comparable to those of previous DSM-IV/DIA-X diagnoses for most disorders. Due to low case numbers for some diagnoses, further research in larger samples is required.