Background Over the last decade, the number of international migrants has increased by more than 60% globally (150 to 232 million). Generally low-skilled or un-skilled, they are concentrated in “3D” (dirty, dangerous, difficult) jobs in the unregulated sector where they face increased risk of illness, injury and abuse. As international migration rates rise, so does the need for the generation of high-quality data. To date, research has centred predominately on the regulated sector, posing a barrier to the development of effective services for this large, yet overlooked population.

Methods This mixed-methods study (Oct. 2013–Jul. 2015) sought to increase the evidence-base on the occupational health and safety of migrants in Kuala Lumpur, Malaysia. More than 2,500 case files documenting labour rights violations were analysed to identify trends and patterns from 2005 to 2015. In-depth interviews (n = 58) and focus groups (n = 6) were conducted with migrants in the manufacturing, service, construction and domestic work sectors to develop a more nuanced understanding of their experiences with occupational injury and contextual factors impacting care. Interviews covered a range of topics were conducted in a structured, but open-ended manner.

Results Findings illustrate that the majority of workers migrated from Bangladesh (43.7%), Indonesia (12.8%) and Nepal (7.5%). 91.3% experienced working conditions different from what had been promised and only 18.7% had a regular day off. 88.8% did not possess their passports and 4.7% could gain access to them if necessary. Females were more likely to experience verbal (11.5% vs. 65%) and physical (29.8% vs. 17.6%) abuse.

Conclusions Findings illustrate the urgent need to build the evidence base on the occupational health and safety risks faced by migrant workers. This information is critical to improving the health of migrant workers globally.