Clinical manifestations of type 1 (Adult) Gaucher disease usually start in childhood. However, most of the previously published data describe the features of this disorder in adults. We present the clinical and genetic characteristics of 34 children and adolescents with type 1 Gaucher disease evaluated in our clinic during the past two years. Patients were aged 2-18 years; 18 were boys and 16 girls. The majority presented before the age of 10. Growth retardation appeared as a prominent feature, with 26% in or below the third percentile in weight, and 30% so in height, especially in the youngest age group (2-5 years). Anaemia and thrombocytopenia occurred in 80% and 60% of the children, respectively. Hepatosplenomegaly was noted in all the children; only 3 were splenectomized. Skeletal involvement was evident on X-rays in 90% of the patients, but only 50% complained of bone pains. Three patients had severe bone disease, with avascular necrosis of the hip joint. Mutation analysis at the DNA level revealed the 1226/1226 genotype in 12 (35%) patients and 1226/84GG in 13 (38%). Correlation was found between the genotypes and the severity of the disease, including growth retardation. A positive response was documented in all 9 patients who completed 12 months of the recently-introduced enzyme replacement therapy for Gaucher disease.