Although myelodysplasia in adults has been well defined by the FAB group, direct translation of this categorisation to children has been controversial. Consequently, in order to better outline the natural history of the disease, a retrospective analysis of case reports and series published in the English language between 1982 and 1996 of. patients with MDS aged between one day and 16 years was undertaken. The diagnosis and the FAB grouping as outlined in the publications were accepted. Two hundred and sixty patients were described in 19 publications. The median presentation age was 5.43 (mean 3.5, SD 4.83) years and 87 were female. In 16, family history of a related haematological derangement was elicited, while in 42, constitutional alterations were described. Organomegaly was reported in 113 patients. The mean Bournemouth score was 2.51 (SD 1.01). Cytogenetic anomalies were detected in 82/203. Progression of the diagnosis to AML (n=47), RAEB (n=11) or RAEB-T (n=3) was noted in 61, while spontaneous regression was observed in two. Survival was significantly higher in those undergoing BMT (41% of 73) compared to those who received first line induction therapy for acute myeloid leukaemia (11% of 19; p= 0.01) or those managed with supportive means only (24%; p= 0.01). Intensive chemotherapy did not improve the rate or length of survival. Refractory anaemia was diagnosed in 68, while in seven, the hypoplastic variant was described. Here, constitutional abnormalities were noted in a higher proportion (23; p= 0.08). Patients with raeb-t (n=41) were older (mean age 8.71 SD 4.65; p= 7.7 E-5), had a significantly higher Bournemouth score (3.1, SD 0.76; p= 7 E-4) and blood blast number (7.2% SD 6.14; p= 6.3 E-6). Cytogenetics were abnormal in 16/25 and in seven, this derangement involved chromosome 7. Within this group, the disease progressed to AML in 17. Patients with RARS (n=14) were typically female (p= 0.0001), was in association with Pearson's disease in two, and commonly had cytogenetic abnormalities (p= 0.005). Children with CMML (n=60) were the youngest (mean age 2.91 SD 3.3 years; 1 p=0.0001), had a significantly higher incidence of organomegaly(n=52, p= 1 E-6), and prevalence of cytogenetic abnormalities (22/41; p= 0; related to chromosome 7 in 12) than the rest of the population, and seven progressed to AML. Features of JCML were reported in 38, and this diagnosis predominated among younger boys who had higher Hb F levels (mean 30.75% SD 14.23 vs. mean 7.14%, SD 6.48, p=0.00001.6) and blood blast cell counts (13 percent, SD 30.8; p= 0.003). Twenty three patients had abnormalities that involved chromosome 7. Morphologically, five were RA, six RAEB, three RAEB-T and nine CMML. In patients not receiving a BMT, survival was significantly shorter in those with RAEB-T and JCML (mean 0.71, SD 4.65; p=-.0001 and 2.94, SD 1.37 years, p= 0.001) and of less than two years in all. Forty-one percent of patients with RA were surviving at the time of publication. Children with CMML, RARS and RAEB had an intermediate survival with a small proportion alive in the long term. Among those with abnormalities involving chromosome 7, survival was heterogeneous and closely followed their FAB type. We conclude that patients with CMML and JCML disorders behave differently, that chromosome 7 disorders are heterogeneous, and that intensive chemotherapy is no better than supportive measures.