Intensive chemotherapy is mandatory in curative treatment of acute myeloid leukemia (AML), but whether the nutritional status deteriorates during treatment, is unknown. We therefore prospectively examined anthropometric and biochemical nutritional markers during intensive chemotherapy in 26 Russian and 19 Norwegian AML patients during 9 months from diagnosis. Although the body mass index remained unchanged in both cohorts, hand grip strength and triceps skinfold thickness declined (P<0.05) during treatment before normalisation at study end. We detected a similar significant, temporary decrease in albumin, transferrin, testosterone and gonadotrophins in both cohorts. Although the fat-soluble vitamins D and E also displayed such a pattern, vitamin A dropped and remained low throughout the study in both cohorts. The Russian patients reported lower global quality of life, more symptoms and more financial concern than the Norwegians. Our data suggest a catabolic metabolism during intensive chemotherapy for AML, leading to impaired nutritional status, hypofunction of the pituitary-gonadal axis and decreased health-related quality of life.