This study aimed to compare the in vitro effects of chitosan oligomers and polymer with commonly-used plant growth regulators (PGRs) on seed germination, protocorm formation, and organ development in Serapias vomeracea. The effects of N-acetylated (10%) chitosan oligomer mixture (CHI-OM) with a degree of polymerization (DP) between 2 and 15 (5, 10, 15, and 20 mg L-1) and chitosan polymer (CHI-P) with a DP of 70 were compared with commonly-used cytokinins [6-benzylaminopurine (BAP) and kinetin (KIN)], auxins [indole-3-acetic acid (IAA) and indole-3-butyric acid (IBA)], and jasmonic acid (JAS) at 0.25, 0.5, 1.0, and 2.0 mg L-1. The medium supplemented with CHI-P at 5 mg L-1 gave the highest seed germination rate, whereas JAS and CHI-OM triggered protocorm formation better than the all treatments tested. The JAS and IAA treatments resulted in intense browning of the roots. The CHI-P treatments at high concentrations and JAS treatments at moderate concentrations increased mean shoot length while the medium containing KIN at 0.5 mg L-1 induced root elongation significantly. The root elongation-inhibitory effect of chitosan was observed at the higher concentrations of CHI-OM, but the media containing 10 mg L-1 CHI-OM and 15 mg L-1 CHI-P triggered adventitious rooting. However, the highest tuberization success was found after 10 mg L-1 CHI-OM and 0.5 mg L-1 JAS treatments. Tuber development was achieved in the media supplemented with BAP and CHI-OM. This study suggested that well-characterized chitosan could be used as an alternative to JAS and BAP in orchid cultures.