Researchers led by Professor Janaka de Silva, from the University of Kelaniya in Sri Lanka, said snake bites posed an important yet neglected threat to public health.
They believe that between 1.2 million and 5.5 million snake bites may occur annually, but only a quarter of these result in "envenoming", when poison enters the blood stream from a snake's fangs.
Southern Asia bore the brunt of the deaths, with venomous snakes such as cobras and vipers killing 14,000 people each year.
India suffered 11,000 deaths alone, the highest of any single country.
In other parts of the world, notably sub-Saharan Africa, the number of people bitten and killed by poisonous snakes was thought to be greatly under-estimated.
Many victims fail to seek medical help or simply do not receive treatment and their deaths go unrecorded, said the scientists writing in the online journal PLoS Medicine.
Studies suggested that only 8.5 percent of snake bite victims in Nigeria and 27 percent in Kenya sought hospital treatment.
The researchers said: "We estimate that at least 421,000 envenomings and 20,000 deaths occur worldwide from snakebite annually. These figures may be as high as 1,841,000 envenomings and 94,000 deaths."
The researchers said studies in countries that appear to have the highest rates of people being bitten and killed should "urgently" carry out studies to ensure medical resources were available to treat the snakebites.
"Accurate data on the epidemiology of snake bite, globally, will facilitate prioritisation of scarce health care resources for prevention and treatment of this neglected health problem," the researchers said.