Police were called to Sheikh's Store, in Beeston, at 2.40pm yesterday (Sunday) after a man pushed the 28-year-old woman to the floor inside.
He then threatened the woman, who was working in the shop alone, with a kitchen knife and demanded cash.
But she bravely fought back and a struggle broke out between the pair.
She was not hurt.
The man then fled the shop after stealing a quantity of cigarettes from the behind the counter.
Detective Inspector Charlotte Hails, of Leeds District CID, said: "This was a frightening experience for the victim who bravely tried to defend herself against the suspect who was armed with a knife. Thankfully she was not injured.ã€€
"We are carrying out various enquiries in an effort to identify the suspect and would like to hear from anyone who may have seen someone matching his description in the area or who has any information that could assist the investigation."ã€€
The robber is described as white, aged 28 to 35-years-old, around 5ft 5ins tall, skinny, with short hair.ã€€
Anyone with information is asked to contact police via 101, quoting crime number 13160634542.