Pakistan fast bowlers Shoaib Akhtar and Mohammad Asif have been banned from all international and domestic cricket for failing a drugs test.
Shoaib and Asif were Pakistan's first-choice new ball pair
Shoaib, 31, will serve a two-year ban and Asif, 23, will be unable to play for 12 months after testing positive for nandrolone, a banned steroid.
The pair waived their right to have tests on their B samples carried out.
"After a thorough inquiry we feel they failed to prove their innocence," said tribunal chairman Shahid Hamid.
"The process of doping was investigated carefully. We made sure the tests were conducted properly, samples reached the laboratory in Malaysia safely and there was no error in testing in the laboratory.
"Both the players were satisfied and accepted the tests and gave their point of view but after a thorough inquiry and bound by the Wada (World Anti-Doping Agency) and the International Cricket Council (ICC) we reached the decision."
The three-man tribunal panel, also including former Pakistan captain Intikhab Alam and doctor Waqar Ahmed, took the view that Shoaib had knowingly taken the banned substance.
Hamid said the panel showed a degree of leniency to Asif because he had little knowledge about performance-enhancing drugs.
"Asif stopped using them when his physiotherapist asked him to do so," he added.
Both players have a right of appeal to the International Cricket Council, world cricket's governing body, but the PCB has accepted the panel's decision.
The inquiry was launched after Shoaib and Asif were sent home from the ICC Champions Trophy in India, although the tests were carried out three weeks before the tournament began.
We were helpless and our hands were tied
It is the most high-profile drugs case in cricket since Australia's Shane Warne banned for a year in 2003 for testing positive for two diuretics.
And the verdicts round off a depressing period for Pakistan cricket.
In September, national team captain Inzamam-ul-Haq banned for four games for bringing the game into disrepute during the fourth Test in England the previous month.
That was followed by the resignation of PCB chairman Shaharyar Khan and the team's elimination from the Champions Trophy at the first round stage following defeats by New Zealand and South Africa.
Shoaib in full cry is one of cricket's most exciting sights
The suspensions mean Shoaib and Asif will miss next year's World Cup in the Caribbean and some observers believe it may be the end of Shoaib's chequered international career after 42 Tests and 133 one-day internationals.
Known as the Rawalpindi Express, he is the quickest bowler in world cricket, having broken the 100mph mark during a game against England at the 2003 World Cup.
Prior to his appearance before the tribunal, he insisted he had never knowingly taken performance-enhancing substances.
"I have always played the game fair and I give 100% and do not feel that I need to take drugs to help my bowling," he said.
But that claim was discounted by the tribunal.
"Akhtar contested the case saying that he has been on a high-protein diet which contained beef, chicken meat and other dietary supplements and also said he took some herbal medicines from a hakim [herbal expert] but he couldn't prove it," said Hamid
Asif, who only established himself in the national team earlier this year, has not so far made any public comment about the matter.