"I will take full responsibility for the failure of this campaign to gain traction," Hunter said in a speech to campaign volunteers, friends and onlookers.
Hunter acknowledged that his run never gained popular momentum, but he felt he scored a political victory in forcing other campaigns to take on issues he championed, including border security, the economic threat of China and rebuilding the military.
"So I think that in itself is a great victory for this campaign," he said.
The decision to withdraw comes after a poor showing in the Nevada caucuses.
A Vietnam veteran, Hunter (R-Alpine) was elected to Congress in 1980 as part of President Reagan's sweep.