According to the Swedish Ethics Review Act, research involving personal data on crimes should undergo independent ethics review. To explore the reporting of ethics approval, we extracted information from articles with Swedish personal data on crimes published in 2013–2021. Of the identified 298 articles, 92 (31%) failed to report ethics approval. Failures were particularly common in articles with a qualitative design, single or few authors and when there was a social science focus. Failures varied markedly between universities. We conclude that failures to report compulsory ethics approval are common in articles involving personal data on crime and that these failures vary markedly with the research setting. Several indicators of poor adherence to the Ethics Review Act have been identified.