Besides cost overruns, the Government Accountability Office found the systems are delivered about two years late on average, The Washington Post reported Tuesday.
"It's not getting any better by any means," Michael Sullivan, director of the GAO's acquisition and sourcing team, told the Post. "It's taking longer and costing more."
The GAO selected 72 of the 95 systems to examine, based on high-dollar value and congressional interest.
Pentagon spokesman Chris Isleib said in a statement, "We'd like to look at what GAO has said and then at the appropriate time make an informed comment."
The Pentagon doubled the amount it has committed to new systems from $790 billion in 2000 to $1.6 trillion last year, the 205-page GAO report said.
"In most cases, programs also failed to deliver capabilities when promised," the report said, meaning more money is spent maintaining existing systems.
Sullivan told the Post three reasons led to overruns and delays: Too many programs chasing too few dollars; technologies not mature enough to go into production; and design, development and production of a system taking too long.