Aim. Assessment of adherence to dietary recommendations by children and adolescents during steroid therapy in the treatment of acute lymphoblastic leukemia (ALL).Material and methods. The study was conducted among parents of children with ALL, aged from 1 to 17 years, treated at the Department of Paediatrics, Hematology and Oncology of the University Clinical Centre in Gdańsk. The paper uses the method of a diagnostic survey, the questionnaire technique. The research tool was an anonymous self-constructed questionnaire.Results. The study included 16 parents (44.4%) of female children and 20 parents (55.6%) of male children. Normal body weight was found in most of the children (22/36 children). Grade 1 hypertension was found in 15/36 children and grade 2 hypertension in 6/36. In 31/36 children, the blood glucose level was 70-180 mg%. The number of 22/36 examined children used a diet with a low glycemic index. As many as 29/36 parents of children and adolescents with ALL followed the diet recommended by a doctor.Conclusions. 1) Most children with ALL have normal body weight during steroid therapy. 2) Children with ALL are subject to arterial hypertension during steroid therapy. 3) Most parents or legal guardians of children and adolescents with ALL adhered to dietary recommendations during steroid therapy.