Back-row Colin Charvis claimed one of the Dragons' five tries
Bucuresti 29 (10)
Tries: Fercu 2, Ciuntu, Vlad, Barbuliceanu.
Cons: Dumbrava, Barbuliceanu.
Dragons 39 (24)
Tries: Emerick, Black, Charvis, Baber,
Cons: Sweeney 4.
Pens: Sweeney 2.
Newport-Gwent Dragons found Bucuresti a tougher proposition on their home turf but held off the Romanians for a five-try Challenge Cup victory.
Last week the Dragons beat Bucuresti 66-10 but were put under intense pressure at the Steaua Stadium.
But tries from Paul Emerick, Adam Black, Colin Charvis, Gareth Baber and Aled Brew proved enough.
Catalin Fercu led Bucuresti's reply with a brace, Stefan Ciuntu, Dan Vlad and Adrian Barbuliceanu also scoring.
The bonus-point win leave the Dragons in second place in Pool 1, three points behind Bristol who they host at Rodney Parade in the next round in January.
Bucuresti: D Dumbrava; C Fercu, C Dascalu, C Gal Minya, S Ciuntu; I Dimofte, A Lupu; N Nere, M Mihalache (capt), P Ion, N Rus, C Tatu, S Burcea, M Macovei, C Mersoiu.
Replacements: F Dobre, M Adascalitei, D Carpo, M Baraulea, V Calafeteanu, D Vlad, A Barbuliceanu.
Dragons: K Morgan (capt); G Wyatt, P Emerick, A Smith, N Brew; C Sweeney, G Cooper; A Black, K Crawford, L Harrison, P Sidoli, L Charteris, M Owen, C Charvis, N Fitisemanu.
Replacements: R Wilkes, J Corsi, I Gough, J Ringer, G Baber, M Hercus, A Brew.
Referee: Carlo Damasco (Italy).