Ester Uwanoghor, 68, was last seen leaving Brixton Recreation Centre at about 4pm on Tuesday, 15 December.
She is a light skinned black female of slim build. She was wearing a pink headscarf with multicoloured dots, a full length pink dress with multicoloured dots (which matched the scarf) a white hoody, a black threequarter length coat with a brown fur neck lining. She also wears glasses.
Officers are increasingly concerned, as Ester is not familiar with the area and she may become confused.
Anyone who has seen Ester or knows of her whereabouts should call Lambeth Missing Persons Unit on 020 8649 2112 or call the police non-emergency line on 101.