STORY: Ugandan television showed damaged buildings inundated with mud from the landslide in Kases, with debris from people's belongings and vegetation caught in the remains of the buildings.
Most of those killed were women and children, Uganda Red Cross spokeswoman Irene Nakasita said in a statement.
She said at least six people had been rescued and transferred to a nearby hospital.
Kasese district, where the disaster occurred, is prone to landslides, especially during the rainy season, because it sits in the foothills of the Rwenzori mountains that straddle the border with Democratic Republic of Congo.
After a prolonged drought, heavy rains have fallen on much of Uganda since late July, causing deaths and flooding and the destruction of crops, homes and infrastructure.