In this study the applicability of two multidimensional instruments, the NHP and the RAND 36-item Health Survey 1.0, for measuring health status in population surveys was examined. A population sample of 1,063 persons aged over 17 years participated in the study. It was shown that, as compared with the NHP, the RAND 36-Item Health Survey 1.0 is a more reliable measure of health status. Second, within a group of subjects who scored 'zero' on the NHP, considerable dispersion in RAND 36-Item Health Survey 1.0 scores was found. For the whole group, no significant differences were found in the amount of variance explained by the corresponding scales from both instruments in the prevalence of chronic diseases. However, among subjects with a zero score on the NHP, the RAND 36-Item Health Survey 1.0 scores were still predictive of the occurrence of chronic diseases. It was concluded that, compared with the NHP, the RAND 36-Item Health Survey 1.0 seems to be a more sensitive instrument for the use in population samples.