Since the beginning of the COVID-19 outbreak in China in December 2019, the epidemic has continued to spread globally. Despite continuous reports of clinical trials being launched, no studies have yet systematically summarized and analysed their characteristics. Our objective is to do this by reviewing trials registered at ClinicalTrials.gov. We searched the ClinicalTrials.gov database and retrieved all clinical trials on COVID-19 registered up to and including 3 April 2020. We summarized the characteristics of the trials, presenting the results of all trials, all intervention trials and drug intervention (including vaccines and traditional Chinese medicine) trials. We identified 306 COVID-19-related clinical trials. Seven of the studies had been withdrawn, leaving 299 active trials. Of the trials, 28.8% were planned to be conducted in Asia, 26.8% in Europe and 18.7% in North America. Most (73.0%) proposed trials expected to recruit fewer than 500 people, and only 22.1% of the studies included children (aged <18years). About two-thirds (67.2%) of the studies were funded by the own resources of medical or research institutions. Of intervention trials, 73.9% used random allocation, and 73.4% used parallel assignment. Only 36.7% of the intervention trials used blinding. In terms of drug trials, 147 trials were drug intervention studies, covering 80 conventional drugs and seven traditional Chinese medicine drugs. Antiviral drugs and antimalarial drugs were the most commonly studied drugs with 52 and 45 trials registered, respectively. Five registered clinical trials were on vaccines. A large number of COVID-19-related trials have been registered within the first 4months since the first infection was reported. These involve a large number of different drugs, the most common being antiviral drugs and antimalarial drugs. More attention should be paid to adequate blinding in future trials.