Human rights due diligence (HRDD) is a key concept of the UN Guiding Principles on Business and Human Rights (GPs)... However, there is limited information available as to how companiesare actually conducting HRDD consistent with their responsibility to respect human rights under the GPs... This article provides much-needed detail – based on empirical research through surveys and interviews – as to what a widespread range of companies are doing in this area, and innovatively analyses these data in the context of current legal developments... [T]his article considers to what extent, if at all, companies are currently undertaking HRDD, with a focus on four broad and diverse sectors: mining and energy, financial services, health sciences and pharmaceuticals, and technology... Our research clearly demonstrates that a company which undertakes dedicated HRDD – with a human rights lens – is much more likely to identify adverse human rights impacts than through its ordinary non-specific HRDD (such as labour procedures or health and safety processes). It also showed that existing non-specific HRDD may not be adequate for raising awareness of third party impacts.