A 7.5 year old boy with myelodysplastic syndrome (MDS) of CMML type associated with trisomy 8 and elevated hemoglobin F (Hb F) value is presented. Hematological evaluation of the patient revealed that the Hb was 10 g/dl, MCV 110 FL, platelets 58 X 10(9)/l, WBC 5.4 X 10(9)/l with 24% atypical monocytes. Karyotype analysis revealed 47, XY, +8. Hb F value was 21% which was distributed heterogeneously among red cells. PCR amplified cDNA copies of circulating reticulocyte mRNA were used to measure the relative amounts of alpha-, beta-, and gamma - globin. There was marked increases in both alpha/beta mRNA ratio (20%) and gamma/(gamma+beta) mRNA ratio (35%) in the patient compared to normal subjects. The study indicated that increased transcription of alpha and gamma genes are partly responsible for the elevation of Hb F in MDS.