Erie County, New York, District Attorney Frank Sedita said a three-month investigation found that physical and forensic evidence "tend to contradict" the accuser's claim that she was raped on Aug. 2 at Kane's offseason home outside Buffalo.
"The totality of the credible evidence -- the proof -- does not sufficiently substantiate the complainant's allegation that she was raped by Patrick Kane and this so-called 'case' is rife with reasonable doubt," Sedita wrote in a statement released Thursday.
He said he will not present the case to a grand jury for possible charges.
"I have repeatedly said that I did nothing wrong," Kane said in a statement Thursday. "I have respected the legal process, and I am glad that this matter has now been closed, and I will have nothing further to say going forward."
Sedita said the reasons for dropping the case include "significant material inconsistencies" in the accounts of the accuser and other witnesses and that physical evidence tended "to contradict" her claim that she was raped on Kane's bed.
In addition, results of DNA tests couldn't back up the accuser's claim of penetration, which is a required element of proof for a rape charge, according to the statement.
The decision comes after the accuser notified authorities that she no longer wished to cooperate with the investigation, Sedita confirmed Thursday.
It ends a high-profile investigation that led to Kane's removal from the cover of EA Sports' "NHL 16" and chants of "She said no!" and "No means no!" during a couple of early road games directed at the Blackhawks' star winger, a former No. 1 overall draft pick.
"We knew all along that Patrick didn't do anything wrong," his agent, Pat Brisson, said in a statement. "We are pleased with the results from the investigation. It's finally concluded."
Added Kane's attorney, Paul Cambria: "I agree that the case is rife with doubt."
The accuser's lawyer, Roland Cercone, did not immediately return a message to The Associated Press.
It's not immediately clear whether Kane could face disciplinary action from the NHL.
"In light of the statement issued today by the Erie County District Attorney's Office, as an internal League matter, we intend to promptly review the information that may now be available to us," deputy commissioner Bill Daly said in a statement. "We will have no further comment until we have completed that review."
The accuser first contacted police with her allegations in August, saying Kane attacked her at his home after they met at a Buffalo nightclub. The woman was examined by doctors, and police investigated Kane's home in Hamburg, New York. The case took a strange turn in September when the accuser's lawyer quit the case after the woman's mother was allegedly involved in a hoax designed to cast doubts on how the police handled the DNA evidence in the case.
At 26, Kane is one of the NHL's top young stars. He has won three Stanley Cup championships in Chicago over the past six years, including last season. He had been in trouble before, arrested after an altercation with a cab driver in Buffalo in the summer of 2009.
He stayed out of sight after the investigation became public and then reported to training camp with the rest of the Blackhawks in September. With the team facing heavy criticism for allowing him to play during the investigation, Kane was joined by top Blackhawks executives for a news conference in which he said he would be absolved of any wrongdoing and brushed aside any questions that touched on the situation.
"The very difficult part of this is when you are basically an international sports star, and as a result a likely target," Cambria said Thursday. "And you have to go through three months of reading things in the media that you know are not true, and they're hurtful things and accusatory things. That's a very difficult burden to bear."
Kane leads Chicago with eight goals and 10 assists this season, and he has a point streak of eight games.
"The Chicago Blackhawks organization has taken this matter very seriously and has tried to navigate a very sensitive situation while continually respecting the legal proceedings," the team said in a statement. "At this time we will have no further comment."
ESPN Staff Writer Scott Powers and The Associated Press contributed to this report.
Patrick Kane won't face rape charge
ESPN legal analyst Lester Munson explains the Erie County district attorney's decision to not charge Patrick Kane with rape.