Abstract. P. DELFORGE.- Contribution to the knowledge of the orchids of the south-west of Cyprus and remarks on some Mediterranean species [Natural. belges (Orchid. 5) 71 (1990): 103-144]. Recent studies on critical groups of Orchidaceae in the south-west of Cyprus and somewhere else result in new systematic views. Observations on the genus Orchis lead to the recognition of the specific level for O. troodi from Cyprus and O. sitiaca from Crete. For the genus Serapias, a new species, which looks like an allogamic dark S. parviflora, is described as S. aphroditae sp. nova; the presence of S. parviflora and S. vomeracea s.st. is confirmed for Cyprus, S. apulica is combined at the specific level and S. hellenica Renz is determinated as the probably correct name for S. columnae. The O. umbilicata group includes, in Cyprus, O. umbilicata (= O. attica), O. flavomarginata, O. lapethica, O. kotschyi and O. rhodia, which is elevated to the specific level; O. oestrifera and O. bremifera are doubtful taxa who indicate probably members of the O. umbilicata group. Into the O. holoserica - O. scolpax complex, O. bornmuelleri seems closely related with the O. umbilicata group; it looks to be member of a group of O. holoserica with considerable pilosity with, among others, O. candica, O. holoserica subsp. heterochila, O. umbilicata subsp. khuzestanica and O. bornmuelleri subsp. carduchorum, these last two being elevated at the specific level. The O. mammosa group, who is not closely related to the O. sphegodes group, is represented, in Cyprus by at least 4 species: O. mammosa, O. transhyrcana, O. sintenisii, O. "pseudomammosa" and, perhaps, O. aesculapii; there is no evidence for the presence of any member of the O. sphegodes group in Cyprus. It is suggested that O. "pseudomammosa" is a species with broad East-Mediterranean distribution. Description of 5 orchid hybrids found in Cyprus is given: Ophrys ×jansenii (O. bornmuelleri × O. sicula), O. ×caillauana (O. bornmuelleri × O. transhyrcana), O.×kreutziana (O. kotschyi × O. mammosa), O. ×demangeana (O. sicula × O. transhyrcana) and Serapias «mastiana (S. aphroditae × S. hellenica). An updated list of species is provided as well as the list of localities prospected in Marsh and April 1989.