Karyotypic analyses were made using root tip mitosis in 10 collections representing 8 species of South Indian Myrtaceae. First records of chromosome numbers have been made in Rhodomyrtus tomentosa (2n=22 and n=11), Syzygium calophyllifolium (2n=22), S. jambolanum (2n=22 and n=11), S. montanum (n=11), Eugenia caryophyllata (2n=22) and Eucalyptus torelliana (n=11). Meiotic studies were made in 10 species. Eventhough all the species mitotically studied possess 22 chromosomes as diploid number, karyotype alterations together with polyploidy play important role in speciation in Myrtaceae. The species meiotically studied show 11 bivalents in PMCs as haploid number.