Abstract This study was carried out to investigte the biotechnology laboratory of Department of Field Crops, Ankara University with the aim of investigating the optimum parameters of gene transfer to mature embryo and leaf segment explants of Triticale (x Triticosecale Wittmack) via particle bombardment (Biolistic) method. Mature embryo and leaf segment explants obtained from Triticale (x Triticosecale Wittmack) were bombardment with accelerated gold or tungsten particles coated with the plasmid pBI221.23 containing the b-glucuronidase (GUS: uidA) marker gene. Different bombardment distances from the stopping plate (6, 9, 12, cm) and different rupture disk pressures (900, 1100, 1550 psi ) were used as physical parameters. Blue cells expressing the b-glucuronidase gene were detected by using a histochemical assay. The variation in the number of blue spots in bombarded explants was used to determine the gene transfer efficiency. The mature embryos of triticale were found to be more amenable for the direct delivery of foreign DNA by the particle bombardment technique than the leaf segments. Also the gold particles were more suitable than tungsten particles in the gene transfer efficiency. The highest gene transfer results were obtained in mature embryos when 6 cm bombardment distance and 1100 psi rupture disk pressure were used.