Evans, who was released in 2014 after serving half of a five-year sentence for the rape of a 19-year-old woman, had the conviction quashed by the Court of Appeal in April.
He faces retrial in October having pleaded not guilty at Cardiff crown court last month.
The 27-year-old, who has always denied the charges against him, played his last professional match in 2012.
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Chesterfield chairman Dave Allen said: "We are delighted to have secured the services of an outstanding footballer, who is now keen to get back to work and score goals.
"Chesterfield Football Club have given a great deal of thought to this signing and following the court's decision, we are in no doubt that Ched Evans should be welcomed back into his profession as a professional footballer."
Evans, who said he was both excited and privileged to be resuming his career at Chesterfield, previously played for Manchester City, Norwich and Sheffield United.
He had been lined up to join Oldham Athletic in January 2015 before that deal was called off following sponsor pressure, the BBC reported at the time.
Evans also had an offer to use Sheffield United's training facilities withdrawn in November 2014 after an online petition against the move, while British Olympic gold medallist Jessica Ennis said she would ask the club to remove her name from a stand at the club's ground if it offered Evans a new contract.
(Editing by Angus MacSwan)
