Cash-strapped Mark Amodei is dropping out of the packed Republican Senate primary.

“While I sincerely believe depth of experience and depth of knowledge about our issues and communities are credentials which are primary in any candidate evaluation, access to the monetary resources to showcase those credentials is also a necessary requirement to mounting a viable primary campaign,” Amodei, a state Senator, wrote in a lengthy e-mail to supporters.

“Voters are drawn to those candidates who expend the largest sums,” the Monday e-mail said.

Amodei raised just $66,000 for his campaign and had $10,000 in cash on hand at the end of the year.

He declined to endorse anyone in the Republican primary.

His departure leaves four leading GOP candidates battling for the nomination to take on Senate Majority Leader Harry Reid (D). They are former state Sen. Sue Lowden, Las Vegas real estate developer Danny Tarkanian, former state Assemblywoman Sharron Angle and longtime New York City investment banker John Chachas.

Reid’s vulnerability — he trails several Republican candidates in recent polling — initially attracted a massive field of would-be challengers, but it has started to dwindle as the March 12 filing deadline nears.

A 12-person GOP field has now dropped to nine.