It's another setback for the South Korean company in a globe-spanning legal battle with Apple, where each accuses the other of patent violations.
The judge in Washington ruled Friday that Apple doesn't violate four Samsung patents, saying the patents don't apply to any U.S. industry.
That will make it harder for Samsung to press the case before the full trade commission, says patent litigation expert Florian Mueller.
Three weeks ago, a jury in California ruled that Samsung owes Apple $1.05 billion for violating patents on features of the iPhone and iPad.
Apple started taking orders for its new iPhone on Friday.