OBJECTIVE: To study the quality of malaria case management of underfives at health facilities in a rural district, 2 years after the Tanzanian malaria treatment policy change in 2001. METHODS: Consultations of 117 sick underfives by 12 health workers at 8 health facilities in Mkuranga District, Tanzania were observed using checklists for history taking, counselling and prescription. Diagnoses and treatment were recorded. Exit interviews were performed with all mothers/guardians and blood samples taken from the underfives for the detection of malaria parasites and antimalarial drugs. Quality of care was measured using indicators adopted from the integrated management of childhood illnesses multi-country evaluation. RESULTS: Quality of care measured by indicator scores averaged 31% of what was considered optimal. The poorest results were for history taking. Nevertheless, 89% of febrile children were treated with antimalarials, in line with national guidelines for fever treatment. Of these, 61% had a parasitaemia > or =2000/microl. There was no difference in treatment given to those with parasitological malaria compared with those without parasites. Pre-treatment levels of chloroquine and sulphadoxine/pyrimethamine were low and detected in 2% and 13%, respectively. CONCLUSION: Although most febrile children were given antimalarial treatment, quality of care in terms of history taking and counselling was sub-optimal. Despite this, the study community had changed behaviour from self-treatment to seeking care at health facilities. This is encouraging for introduction of artemisinin-based combination therapies policies as one could focus resources into improving care at health facilities and still reach out with treatment to most febrile children.