"Today (Tuesday) we have registered a total of 141 deaths and 7,777 cases of the disease reported," doctor Agistinho Pedro Semedo, who heads the Simao Mendes hospital in the capital Bissau, told AFP.
About 120 people had been reported dead on September 7.
Simao Mendes is the biggest hospital in the West African country and is coordinating Guinea-Bissau's national anti-cholera program.
There are currently 136 cholera patients, including 30 children under the age of five, being cared for in the hospital, Semedo said.
"Between Monday and Tuesday we received 30 patients. We are really snowed under and the patients keep coming," he said.
Cholera is an intestinal bacteria that causes serious diarrhoea and vomiting leading to dehydration. With a short incubation period, it can be fatal if not treated within 24 hours.
Experts say the number of people infected with cholera could be much higher than the cases officially reported.
Some of the infected people hide from health officials, according to local health authorities in the Bandim neighbourhood of Bissau, which has been heavily affected by the epidemic.
"There are a lot of taboos surrounding the illness. Parents do not want to tell the health officials of cases of infections in their families," said Mariama Balde, who mans a local health station in Bandim.
In 2005 a cholera epidemic in Guinea-Bissau killed 400 people and infected over 4,000 people.
"We don't have the same figures as in 2005 yet but if nothing is done we could surpass them," El Hadji Lamine Indjai, spokesman for the national anti-epidemic program, told AFP.
The United States embassy in Dakar announced Tuesday that it will give 100,000 dollars (71,000 euros) to the UN's children's fund UNICEF to help combat cholera in schools.
The US embassy cited figures from the Guinea-Bissau health ministry which show that 900 new infections occur every week and the mortality rate is at 12.4 percent.