Randstad ranked as the largest provider of office/clerical staffing in the U.S., and ManpowerGroup Inc. (NYSE: MAN) ranked as the largest provider of industrial staffing in the U.S.

The information comes from the newly released 2012 List of Largest U.S. Office/Clerical Staffing Firms and 2012 List of Largest U.S. Industrial Staffing Firms.

Among office/clerical staffing providers, the three largest U.S. providers are:

1. Randstad
2. Aerotek (Allegis Group)
3. Adecco

Fourteen firms in total qualified for the list of largest U.S. office/clerical staffing firms. In order to qualify for the list, firms must have had at least $100 million in office/clerical staffing revenue in 2011.

Among industrial staffing providers, the three largest U.S. providers are:

1. ManpowerGroup
2. Aerotek (Allegis Group)
3. Express Employment Professionals

In all, 25 firms qualified for the list of largest U.S. industrial staffing firms. In order to qualify for the list, firms must have had at least $100 million in industrial staffing revenue in 2011.

Corporate members of Staffing Industry Analysts can download the list of largest office/clerical staffing firms by clicking here, and can download the list of largest industrial staffing firms by clicking here.