We investigated double (specific and nonspecific) esterase (DE) staining in marrow cells of 237 patients with the myelodysplastic syndromes (MDS). Additional abnormalities of neutrophilic granules were examined cytochemically and immunocytochemically for myeloperoxidase activity and antigen elastase, lactoferrin and CD15 granule-membrane glycoproteins. Abnormal DE staining (>/=3% of all nucleated marrow cells) was present in 27% of patients with no difference among different MDS subtypes. However, the prevalence of high abnormal DE staining (>/=10%) was significantly lower in refractory anemia with excess blasts in transformation (1%) compared to other MDS subtypes (12-15%; p = 0.004). The prevalence of other granule abnormalities was not statistically different in the DE normal and DE abnormal groups. Abnormal DE staining is relatively common among all MDS subtypes. High DE staining may identify a subgroup of patients with a lower grade MDS.