What caused the stampede is still unclear, one official who refused to be named said people were crushed after the president left the rally and the crowd rushed to get out of the stadium in the southern province of Ibb.
While other reports say the stampede occurred with people tried to gain entry into the sports stadium which was already crammed.
It’s believed 150,000 people were inside the building, with people standing on the ground as well as in the stands. A large number of people were also outside on the streets surrounding the stadium.
Bodies and injured people were seen lying on the ground as rescue teams, police and ambulances rushed to the scene to take the injured to hospital.
"The president promised to compensate the families who lost a relative today. They will receive monthly salaries," said the official.
A similar election rally in Taiz province, 250 kilometres southwest of the capital Sanaa, killed at least four people and inured 10 government officials said without giving further details.
Yemen will hold presidential and local council elections on September the 20th. In the leadup to the election, the country’s long serving president Ali Abdullah Saleh is touring the poor country to drum up support for his campaign.
Mr Saleh, who faces four challengers, is widely expected to win the presidential polls. The 64 year old field marshal has been at the helm since 1978, first as president of the then North Yemen and then as leader of the unified state after north and south merged in May 1990.
The Ibb constituency, with 900,000 voters, is the second most important in Yemen after the capital Sanaa. It is an opposition stronghold.
Previous elections have been marred by shootings between members of rival parties in Yemen, where many people carry arms, but stampedes are unusual.
Kidnapped
Meanwhile, Tribesmen have abducted four French tourists in southeast Yemen on Sunday in an attempt to put pressure on authorities to free jailed members of their tribe. They have threatened to kill the hostages if authorities attempted to use force to free them.
Authorities have dispatched security reinforcements to Shabwa province, where the four French tourists were taken.
"Large numbers of army troops and security forces were sent Monday night to the zone in Shabwa where the captors are holding the hostages," some 60 kilometers (35 miles) from Ataq, where they were kidnapped, an unnamed government source said.
He added that authorities were continuing negotiations with the kidnappers for the release of the hostages.
"We are disappointed that the negotiations were not successful this evening," a French diplomat in Sanaa was quoted as saying by the SABA news agency.
More than 200 foreigners have been kidnapped in Yemen in the past 15 years, particularly between 1991 and 2001.
The hostages are usually released unharmed, but three Britons and an Australian seized by militants were killed when security forces stormed their hideout in December 1998.