The aim of presented investigation was to determine the composition of scale insects species and intensity of their occurrence on some greenhouse’s ornamental plants. The investigations were carried out in the greenhouse of Maria Curie Skłodowska Botanical Garden in Lublin in years 2002–2004. Eight species belonging to seven botanical families were observed: Abutilon striatum cv. Thomsoni, Cyrtomium falcatum Presl., Dizygotheca elegantissima (Veitch), Hedera helix L., Hypoestes phyllostachya Presl., Nerium oleander L., Passiflora guadrangularia L., Ruscus aculeatus L. The quantitative analysis of the studied material was performed making use of the following ecological indicators: number and density. Identification of the scale insects species was performed on the basis of microscope slides. Three species of the scale insects belonging to three families were observed on ornamental plants: Pseudococcidae [Pseudococcus maritimus (Ehrh.)], Coccidae [Saissetia coffeae (Walker)] and Diaspididae (Aspidiotus nerii Bouchè). The scale insects were noted on all species of studied plants. Observed scale insects are typical polyphagous and all of them are considered as harmful pests in greenhouses. Among scale insects inhabiting this group of plants distinctly numerous on particular host plants were S. coffea and A. nerii. On the studied plants scale insects were stated at four degree of density.