The incident happened late Friday after heavy rainfall when sections of the landfill collapsed, covering some nearby houses, Ugandan media reported.
Kampala Capital City Authority said government and Red Cross personnel were searching the site and had rescued 14 people.
“On a very sad note, eight people have so far been found dead, six adults and two children. The rescue operation is still ongoing …,” the authority said on its X account.
The landfill, known as Kiteezi, has served as Kampala’s sole garbage dump for decades and had turned into a big hill. Residents have long complained of hazardous waste from the site polluting the environment and posing a danger to people.
Footage from NTV Uganda television showed people walking on a section of the landfill that had crushed parts of a house, while pictures from UBC Uganda showed an excavator attempting to dig up garbage.
Parts of Uganda have been experiencing heavy rains in recent weeks causing flooding and landslides, though no fatalities had previously been reported.