|Date of birth||16 May 1971|
|Place of birth||Galaţi, Romania|
|Height||1.75 m (5 ft 9 in)|
|1997||→ Samsung Bluewings (loan)||6||(2)|
|2001||→ Rapid Bucureşti (loan)||9||(5)|
|* Senior club appearances and goals counted for the domestic league only.
Born in Galaţi, Galați County, Barbu started his professional career with FC Argeş Piteşti, helping it achieve promotion from the second division in 1994 while scoring 89 goals during his seven-season spell (safe for a short spell with South Korea's Suwon Samsung Bluewings).
Midway through 1998–99, Barbu signed with FC Rapid Bucureşti, helping the capital club to the Liga I title with eight goals in only 11 matches. He was also crowned the competition's top scorer the previous campaign with 21 for Argeş Piteşti, despite missing several games due to his time in Asia.
For 1999–2000, Barbu moved to Spain and joined La Liga strugglers CD Numancia. He netted six goals during that season, helping the Soria side barely avoid relegation. During his second year – which he finished with Rapid – he was joined by compatriot Laurenţiu Roşu.
Barbu retired in 2004 after spells with old team Argeş and CS Dacia Mioveni, the last in the second level. With Rapid, he appeared in two UEFA Champions League matches and scored once, adding six appearances in the UEFA Cup (four goals, for Piteşti).
He also netted in his last, against Greece.
- Results list Romania's goal tally first.
|6 September 1997||Sportpark, Eschen, Liechtenstein||Liechtenstein||7–0||8–1||1998 World Cup qualification|
|8 April 1998||Stadionul Steaua, Bucharest, Romania||Greece||2–0||2–1||Friendly|
- El Numancia hunde más al Atlético (Numancia sinks Atlético further); Marca, 25 March 2000 (in Spanish)
- El Numancia acaricia la salvación tras ganar al Espanyol (Numancia caressing salvation after defeating Espanyol); El País, 7 May 2000 (in Spanish)
- El Alavés entra en lista de espera (Alavés joins waiting list); El País, 15 May 2000 (in Spanish)
- La Federación deniega la licencia de comunitarios a cinco jugadores La Federación deniega la licencia de comunitarios a cinco jugadores (Federation denies EU-licence to five players); El País, 26 January 2001 (in Spanish)
- "Constantin Barbu". European Football. Retrieved 4 November 2015.