The Spanish woman, who has not been named, walked into a police station in the town of Dos Hermanas, near Seville, on Saturday night and confessed to the killing.
The 44-year-old was accompanied by her siblings and seemed in an "intoxicated" state and told officers that she had killed a man and stored his body in the freezer of Heladería Otoño, a local ice-cream shop, reported Europa Press.
The man is believed to have been 62-years-old, married and the father of five children. He had been missing for around 24 hours.
Police were carrying out an post mortem on the man's body on Sunday, and confirmed that there "had been no apparent relationship between the arrested woman and the dead man".
Police confirmed that there was no familial link between the pair and they were not believed to have known each other.
Various media reports have named the woman as the owner of the ice-cream shop, but police have yet to confirm her identity. They searched the shop after taking the woman's statement and discovered the body of the man inside the freezer.
The woman was immediately arrested and charged with murder.
Despite confessing to the crime, the woman provided no reason for murdering the man. Police are currently trying to establish the motive for the murder.