CONTEXT: One potential agent to improve symptoms and quality of life (QoL) in advanced cancer patients is adenosine 5'-triphosphate (ATP). Several reports suggest that ATP may positively affect QoL and survival in patients with advanced non-small-cell lung cancer. OBJECTIVES: To investigate the effects of ATP infusions on QoL parameters in patients with preterminal cancer of mixed tumor types. METHODS: Ninety-nine preterminal cancer patients were randomly allocated to receive either ATP intravenously weekly (8-10 hours/week, with maximum 50 mug/kg.minute) for eight weeks or receive no ATP (control group). QoL parameters were assessed until eight weeks and analyzed by repeated-measures analysis of covariance. RESULTS: Fifty-one patients were randomized to the ATP group and 48 to the control group. Unexpectedly, in the untreated control group, most of the outcome parameters did not deteriorate but remained stable or even significantly improved over time. Between the ATP and control groups, no statistically significant differences were observed for the large majority of outcome parameters, except for the strength of elbow flexor muscles in favor of the control group. CONCLUSION: ATP infusions, at the dose and schedule studied, did not have a significant effect on QoL, functional status, or fatigue in preterminal cancer patients of mixed tumor types.