The company headquarters was moved to Elmont, Long Island in 1949. In the early 1950's the DeMatteis family business expanded during the postwar suburban development boom and became the largest builder of public schools on Long Island. In the 1960's as federal, state and local governments directed their energies toward the rebuilding of New York's urban areas, DeMatteis became the leader in the region's renewal activities.

   Leon D. DeMatteis Construction Corporation (LDDCC) is the flagship entity of The DeMatteis Organizations - comprising one of the area's largest, longest established and most respected family owned construction and real estate companies. It's diverse capabilities include general contracting, construction management, design-build contracts, and interior construction and renovation.

   DeMatteis has become recognized as one of the oldest continuously family owned and operated construction companies in New York - and one of the largest such firms in the United States.  Corporate  Design & Realty Magazine has ranked The DeMatteis Organizations among the top 25 real estate developers in the nation. For over eighty six years The DeMatteis Organizations has added to the landscape of the New York metropolitan area while their
commitment to excellence personified by Leon DeMatteis has lived on for three generations