Several authors have described the occurrence of coarse granular cytoplasmic inclusions (the “AlderReilly Bodies”; ARB) in leukocytes of patients with Mucopolysaccharidosis VI (MPS VI; OMIM +253200). Aiming at estimating the frequency of ARB in MPS VI, we analyzed the reports of the peripheral blood counts routinely performed in the MPS VI patients at our hospital from 2002 to 2003 (35 reports of 17 patients; 9/17 patients had two or more evaluations performed in this period). No patient was on enzyme replacement therapy at the time of the blood sampling. The analysis of blood cells was first performed with automation in haematology (Pentra 120-ABX).