Variation in seedlings height and diameter in the zone of root collar of nine European beech provenances from southeast Europe was examined at two trial sites in Serbia (Fruška Gora and Debeli Lug). Provenance trials were established during the spring of 2007 and arranged in randomized complete block design. Results are presented for the seedlings age of 10 years. Provenance means for the studied traits were 267.2 cm and 49.09 mm at site Fruška Gora; and 230.8 cm a nd 33.53 mm, at site Debeli Lug, respectively. Significant site (p<0.001) and provenance (p<0.001) effects were detected in the studied traits. Two out of nine provenances (RS60 and RS69) changed their ranks in height growth across the two sites. The greatest mean value for height growth, at both trial sites, was observed in Serbian provenance RS67 (302.4 cm and 268.4 cm, respectively). The same provenance had the highest mean values of diameter in the zone of root collar (55.9 mm and 39.6 mm, respectively), as well. The presented provenance research results are important for future activities on tree breeding and conservation of the European beech genetic pools.