OBJECTIVE: To examine the relative contributions of mental and physical health to evaluations of health preference for advanced-stage cancer patients in a longitudinal setting. METHODS: We compared changes in the Physical Component Summary (PCS) and Mental Component Summary (MCS) scores of the Medical Outcomes Survey Short Form (SF-36) with changes in the EuroQoL visual analogue scale (VAS) for a sample of advanced-stage cancer patients. Using data collected at baseline and 3-month followup in a multicenter study of 328 cancer patients eligible for phase I clinical trials, we examined correlations among change-from-baseline scores for the PCS, MCS, and VAS. RESULTS: Mean age was 57.5 years; 10 different types of malignancies were represented in the sample. Completers (144 patients who completed both baseline and follow-up questionnaires) had a significantly (p=0.01) higher average baseline PCS score (M=41.5, SD+/- 10.1) than non-completers (M=38.3, SD+/- 12.3), whereas baseline MCS and VAS scores did not differ between the two groups (p=0.74 and 0.28, respectively). Change-from-baseline in the VAS (M=-5.7, SD+/-21.8) was positively correlated (r=0.34, p=0.0002) with changes in the PCS (M=-4.1, SD+/-9.9), and was positively correlated (r=0.23, p=0.0123) with changes in the MCS (M=-1.1, SD+/-9.7). While the distribution of VAS change scores was more piqued, there was greater variability in MCS and PCS change scores. CONCLUSIONS: Changes in overall mental and physical health contribute approximately equally to changes in advanced-stage cancer patients' preferences for their current health states. Our ability to detect strong correlations between changes in the VAS preference measure and changes in the MCS and PCS health status measures was limited by lack of variability in change scores for the preference measure used. Further research should examine longitudinal relationships between other preference measures (i.e. standard gamble and time-tradeoff) and generic health status measures.