Members of the federal jury cried but Dzhokar Tsarnaev remained reactionless as the death sentence was read out in a federal court in Massachusets.
Tsarnaev - wearing a dark sport coat with a light-coloured shirt - had his head bowed slightly, with his hands folded in front of him.
Following the announcement, Judge George O'Toole described the jury as a "model for future juries".
"You have sat through a trial that has had horrible images and poignant testimony," he added.
More top news
The retired handyman defied the heat to come 21st in the veterans’ race in Gawthorpe, West Yorkshire.
There are reports of an explosion on Enterprise Way in Derby.
Today is our warmest Easter Monday recorded - and temperatures will continue to climb as the weekend draws to a close.