The Ospreys have been cleared of fielding an ineligible player in the group stages of the Heineken Cup.
European Rugby Cup Limited, the body that run the Heineken and Amlin Challenge Cup competitions, had been investigating the contract of scrum-half Ricky Januarie.
The former Springbok star joined the Ospreys on loan from Super 14 side The Stormers in November and played in four group matches as Scott Johnson's men beat Viadana in back-to-back ties before they lost to Clermont Auvergne and then toppled Leicester.
ERC regulations state that a player 'must have at least a three-month contract with the club' in order to be eligible for European competition.
Januarie, however, returned to South Africa in January, less than three months after arriving in Wales.
Premier Rugby, the umbrella body for Guinness Premiership clubs in England, reportedly issued a complaint and ERC ordered an investigation.
That investigation concluded on Monday in Dublin with the Ospreys told they had 'no case to answer'.
"Having co-operated fully with ERC at all times during their investigation into this matter, and providing them with all the relevant paperwork relating to Ricky's contract and registration, we are delighted to have been informed that they have found that Ospreys Rugby has no case to answer," said Ospreys managing director Roger Blyth.
"Now that we can finally put this matter behind us, we are, along with our many supporters, looking forward to our quarter-final against Biarritz in San Sebastian on Saturday 10th April."
The WRU has launched a campaign to create a long term legacy for Welsh club rugby by highlighting the advantages of volunteering. Rhian Edwards, a volunteer at Seven Sisters, has enjoyed many benefits of her volunteering at a grassroots rugby club including being part of the Rugby World Cup volunteer workforce after being nominated by the WRU - and the WRU is asking for more people to develop their 'Welsh rugby roots'.
Wales head coach Warren Gatland and captain Sam Warburton say their first prioirty on Sunday in the opening game of the World Cup is to win against Uruguay and not get overly concerned with points difference.
With only days to go until the biggest rugby competition in the world begins, rugby fans visiting Cardiff this autumn will be able to enjoy a special display at National Museum Cardiff as part of the celebrations surrounding the Rugby World Cup.
Geraint John has taken up the new role of WRU elite coach development manager having arrived in Wales last week. WRU TV caught up with him at the WRU rugby department's strategy day at the Millennium Stadium.