A security guard who applied to a government-appointed body for a work permit received someone else's passport and driving licence in the post.
Mr Hussain said it was "very worrying" his passport was missing
Abid Hussain, 23, applied to the Security Industry Authority (SIA) to work at a company in Birmingham.
Mr Hussain, of Stourbridge, said he still did not have his own passport and the mix-up meant he had to miss a family wedding in Islamabad.
An SIA spokesman said the mistake was probably down to "human error".
Mr Hussain completed a four-day course to become a security guard and was then asked to provide supporting documents.
He posted his passport and a bank statement to the authority to get the licence to work at Secure Areas Ltd in Harborne.
But he was sent different documents back by recorded delivery.
The parcel sent to Mr Hussain's home contained a driving licence and passport belonging to a Shazad Hussain, from Birmingham.
When Abid Hussain contacted the SIA he said he was told they had lost his documents.
He said: "Finding somebody else's ID on your doormat is not exactly good is it? And being told that my passport is missing is very worrying.
"It has caused me to miss my cousin's wedding and I am worried about my documents falling into the wrong hands.
"I don't want people getting hold of my bank details either - who knows what they could do with that information."
Mr Hussain's boss, John Day, who is a former policeman said it was "unbelievable" the mistake could have happened.
Mr Day said: "I worked for many years as a policeman and I know how much a passport can fetch on the black market - it is a very dangerous mistake.
"When he called the SIA they just told him they had mixed things up because the two men had the same surname and live in the same region.
"It beggars belief."
Robert Buxton, assistant director of marketing at the SIA, said: "There has been a mix-up.
"This was brought to our attention and we are dealing with the issue.
"We have spoken to both Mr Abid Hussain and Mr Shazad Hussain about it and we are dealing with the situation as soon as we can.
"All supporting documents are scanned and returned immediately."