The myelodysplastic syndrome (MDS) represents a group of clonal hematological disorders characterizedby progressive cytopenia reflecting defects in erythroid, myeloid and mega karyocytic maturation. The incidenceof MDS is greter in older age groups. Detailed studies on MDS from India are not available. Cytogenetic studyusing GTG-banding and FISH revealed 54.5% clonal chromosomal abnormalities. We have carried outchromosomal breakage study from peripheral blood cultures induced with mitomycin C, in karyotypicallynormal MDS (49) and 15 (30.6%) showed significant (p < 0.001) increase in chromosome damage compared tocontrols. Among 22 occupationally exposed MDS, 6 (27.3%) showed a high frequency of chromosome breakagewhile in the non-exposure (n=27) group, high chromosome breakage was noted in 9 (33.3% ) MDS patients.Our results suggest that the high chromosome damage may be due to acquired Fanconi anemia which leads tomultiple defects in chromosomes and clonal chromosome anomalies.