ObjectivesTo assess the diagnostic accuracy of non-invasive or minimally invasive autopsy techniques in deaths under 1 year of age.DesignThis is a systematic review of diagnostic test accuracy. The protocol is registered on PROSPERO.ParticipantsDeaths from conception to one adjusted year of age.Search methodsMEDLINE (Ovid), EMBASE (Ovid), CINAHL (EBSCO), the Cochrane Library, Scopus and grey literature sources were searched from inception to November 2021.Diagnostic testsNon-invasive or minimally invasive diagnostic tests as an alternative to traditional autopsy.Data collection and analysisStudies were included if participants were under one adjusted year of age, with index tests conducted prior to the reference standard.Data were extracted from eligible studies using piloted forms. Risk of bias was assessed using Quality Assessment of Diagnostic Accuracy Studies-2. A narrative synthesis was conducted following the Synthesis without Meta-Analysis guidelines. Vote counting was used to assess the direction of effect.Main outcome measuresDirection of effect was expressed as percentage of patients per study.FindingsWe included 54 direct evidence studies (68 articles/trials), encompassing 3268 cases and eight index tests. The direction of effect was positive for postmortem ultrasound and antenatal echography, although with varying levels of success. Conversely, the direction of effect was against virtual autopsy. For the remaining tests, the direction of effect was inconclusive.A further 134 indirect evidence studies (135 articles/trials) were included, encompassing 6242 perinatal cases. The addition of these results had minimal impact on the direct findings yet did reveal other techniques, which may be favourable alternatives to autopsy.Seven trial registrations were included but yielded no results.ConclusionsCurrent evidence is insufficient to make firm conclusions about the generalised use of non-invasive or minimally invasive autopsy techniques in relation to all perinatal population groups.PROSPERO registration numberCRD42021223254.