The aim of this study was to assess the quality of reporting of harms in hypertension clinical trials identified from the Cochrane Database using the Consolidated Standards of Reporting Trials (CONSORT) extension for harms reporting. Forty-one hypertension trials were included in the study. On average trials reported less than half of the items recommended by the CONSORT extension for harms (mean 9.83 items; 95% confidence interval = 8.06, 11.60). Trialists need to address the perceived shortcomings in measurement, analysis, and reporting of harms data so that the available trial data can be considered as a balanced and reliable source of evidence.