Evans, ranked 108th, failed the drug test at the Barcelona Open in April and went public with the result at an emotional press conference in June.
The 27-year-old's ban has been backdated and he will be eligible to play again on April 24 next year.
"A sample was found to contain cocaine and its metabolite," a statement from the International Tennis Federation read.
"It was agreed that a period of one year's ineligibility should be imposed, commencing on 24 April 2017.
"The ITF accepted Mr. Evans' account of how the cocaine got into his system and that he bears no significant fault or negligence for the violation."
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"Following the announcement made from the ITF today, I want to thank everyone who has supported me throughout this difficult period," he said.
"I am determined to return to the sport I love and compete at the level I know I can in the not too distant future."
Cocaine is only banned in competition and Evans insisted he didn't take it during the tournament.
He said it had got into his system via permitted medication that he had stored in the same pocket of his washbag in which he had previously kept the cocaine.
That explanation, coupled with Evans' prompt acceptance that he had taken the drug, resulted in a more lenient ban that might have been expected.
Martina Hingis received a two-year suspension for a similar offence in 2007, when she failed a drugs test at Wimbledon.
Birmingham-born Evans had enjoyed his best run at a Grand Slam earlier this year when he defeated former US Open champion Marin Cilic en route to the last 16 at the Australian Open.
He also helped Britain win the Davis Cup in 2015 and was ranked a career-high 41 in the world earlier this year.
In the past, Evans has had his funding stripped twice by the Lawn Tennis Association for attitude and behaviour problems.
His rebellious tendencies played a major role in his ranking dropping to 772 in April 2015 before his resurgence earlier this year.