The 27-year-old insisted he took the illegal substance out of competition.
Britain's Dan Evans tested positive for cocaine in April, the World No.50 announced at a press conference.
The 27-year-old said he took the illegal substance out of competition and for reasons "completely unrelated to tennis".
"This is a very difficult day for me and I wanted to come here in person to tell you guys face to face," Evans said at a London Hotel on Friday where he took no questions but made a statement.
"I was notified a few days ago that I failed a drugs test in April where I tested positive for cocaine.
"It's really important you know this was taken out of competition and the context was completely unrelated to tennis,” Evans added.