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Company Profile

Day & Zimmermann is a century-old, family-owned company specializing in construction & engineering, operations & maintenance, staffing, security and defense for leading corporations and governments around the world.

Our vision is to accelerate the next generation of innovation.

Chairman & CEOHarold L. Yoh III
Annual Revenue: $2.4 Billion
Global Workforce: 37,000
Headquarters: 1500 Spring Garden Street, Philadelphia, PA 19130
Media Contact: Matt Rivera

Our customer promise: We do what we say.®

  • Global Workforce


  • Founded in 1901


  • $2.4 Billion Annual Revenue


  • 52+ Worldwide Locations


  • Footprint at 60% of the U.S. nuclear fleet


  • Ranked in Top 100 Defense Companies


  • #1 Ranked Operations & Maintenance Contractor by Engineering News Record


  • Ranked on the Forbes America's Largest Private Companies List


  • Yoh Named to HRO Today’s MSP, RPO and Total Talent Solutions Baker’s Dozen list


Our People
are Our Future

In a constantly changing world it’s not businesses, governments and institutions that will build the future. It’s the people behind them. For more than a century Day & Zimmermann has hired, placed and trained the people that helped bring big ideas to life.

Our People

The best way to learn about life at Day & Zimmermann is to hear from the people who are living it. Meet the people behind our success.

Learn More About Life at D&Z

One of the most challenging, and rewarding, parts of my job is building a high-performing team. The diversity of the team is critical to bringing innovation to the project and delivering success.