The 2006 Croatia Open Umag was the 17th edition of the Croatia Open Umag men's tennis tournament. The tournament was held on outdoor clay courts from 24 July until 30 July 2006. Guillermo Coria was the defending champion but lost in the first round. Unseeded Stan Wawrinka won his first title of his career after Novak Djokovic retired with breathing problems in the tiebreak of the first set.
See main article: 2006 Croatia Open Umag – Singles. Stan Wawrinka defeated 
Novak Djokovic, 6–6 RET
See main article: 2006 Croatia Open Umag – Doubles. 
Jaroslav Levinský / David Škoch defeated 
Guillermo García López / Albert Portas, 6–4, 6–4