The 29-year-old was part of the Czech Republic squad who won the tournament in 2002 after beating France on penalties in the final.
Despite enjoying a glittering career at Stamford Bridge since joining Chelsea in 2004, Cech insists winning silverware for his country was a special moment for him.
"It remains one of the best victories in my career," said Cech.
"I have been playing for one of the best teams in the world for the last seven years. I have won the top league three times and the FA Cup three times. I have lots of victories behind me but the Under-21 win is something special.
"I represented my country and became a European champion. It doesn't matter that it wasn't in the senior category. It is still very precious and not everyone gets to experience such pride."