In this article, the issues involved in the measurements of quality of life in clinical trials of cardiovascular drugs are discussed with emphasis on beta-blocker treatment. The extensive documentation available for beta-blockers makes it possible to evaluate different aspects of this class of drugs. Generally, beta-blockers have been shown to be safe with a low frequency of serious side effects. However, results of different studies have shown that this class of drugs affects various aspects of well-being and psychomotor tests both negatively and positively. Adverse effects often associated with beta-blockers are the subjective symptoms that are considered to be related to the central nervous system. Today there is increasing evidence that these can be quantitatively as well as qualitatively reduced by using beta-blockers in a low dose and avoiding high plasma peak concentrations. Considering effects on well-being and psychomotor tests, there seems to be no clinical difference between hydrophilic and lipophilic beta-blockers, when administered in comparable therapeutic dosages, whereas beta 1-selective blockers in clinically relevant doses seem to produce fewer and less severe adverse effects than nonselective blockers. Compared with other classes of cardiovascular drugs, there is no clear evidence of differences in well-being between selective beta-blockers and angiotensin converting enzyme inhibitors or calcium antagonists.