Background Chemotherapy doses are usually prescribed on the basis of body surface area but dose banding is emerging as an efficient alternative. Dose banding presents the possibility of in-advance preparation in a Centralized Intravenous Admixture Service. Aim of the study To evaluate the long-term stability of 5-fluorouracil at banded doses (700 mg and 800 mg) in polyolefin bags. Materials and methods Ten polyolefin bags were prepared under aseptic conditions and stored at 23 ± 2°C for 24 days. Five of them were composed of 14 mL 5-fluorocuracil (700 g) in 100 mL 0.9% sodium chloride solution and the five other of 16 mL 5-fluorouracil (800 mg) in 100 mL 0.9% sodium chloride solution. At defined times, physical stability parameters were assessed: optical densities, pH measurements, visual and microscopical inspections. Solutions concentrations were measured using high-performance liquid chromatography coupled with a photodiode array detector. Results No change was observed on pH and optical density measurements during the study period. Visual and microscopical inspections remained free of colour change, precipitate, microagregate or crystal. The concentrations of 5-Fluorouracil in 800 mg bags remained stable for 24 days while the concentration in 700 mg bags showed a stability of at least 17 days. Conclusion Five-fluorouracil at banded doses of 700 and 800 mg in polyolefin bags is physicochemically stable for at least 17 days at 23 ± 2°C. These results support the possibility of in advance centralised preparation.