Macrochloroplasts, which can be produced by the imbalance expression of plastid division genes, may act as an alternative target tissue for the transformation of foreign genes especially by particle bombard-ment. This paper reports the production of stable transgenic cauliflower plants expressing cauliflower plastid division gene, BoMinD by using PEG mediated transformation of mesophyll protoplasts. Stabletransgenic BoMinD cauliflower plants had abnormally shaped chloroplasts but these did not exhibit atrue macrochloroplast or minichloroplast phenotype. Transgene number did not relate to the expressionof the BoMinD transgene. Detection of total BoMinD by western blot suggests that the slight increasein total BoMinD levels resulted in honey-comb or doughnut shaped chloroplasts and irregular surfacemembrane chloroplasts.