We report a case of de novo myelodysplastic syndrome with clonal eosinophilia (MDS-Eo) and eosinophilic pulmonary interstitial infiltration, confirmed by autopsy. Cytogenetic study using Giemsa banding identified 47,XY,+1,der(1;7)(q10;p10),+8 in the marrow cells. Simple Giemsa staining revealed the same chromosomal aberration in metaphase spreads with eosinophilic granules, indicating the clonal proliferation of eosinophils. To our knowledge, our case is the 6th reported case of MDS-Eo with cytogenetically confirmed clonal eosinophilia, and the first autopsy of MDS-Eo. A review of the literature combined with our findings suggests that this type of chromosomal aberration might be involved in the as yet unknown pathogenesis of MDS-Eo.