The woman, who cannot be named for legal reasons, had gone out to work leaving her child behind, Wolverhampton Crown Court heard.
She was given a suspended prison sentence by a judge, who had earlier heard that the baby had been left on her own on 'many occasions'.
The court was told that the child had now been taken into care by social services. The woman, from Sandwell, admitted child cruelty and she was given a six-month jail term suspended for 18 months and placed under supervision for a year.
Judge Helen Hughes told the mother who cannot be named for legal reasons: "You deliberately left your baby at home on her own.
"You did it on many occasions and I do not accept you made proper arrangements for her care.
'"But I do accept the child was well fed, the flat was clean and she had food and drink."
She told the mother: "She was only 20 months old and she was vulnerable. The fact you were out at work is no mitigation for what was serious misconduct to a child."
Alka Brigue, prosecuting, told the court the child was found by a bailiff attending a neighbouring flat and he quickly notified police.
The child was able to roam around but the kitchen and toilet doors were closed, the TV had been left on and there were crisps on a plate and a bottle of juice.
Miss Kate Thomas, defending, said the mother had not left the child to go partying or drinking and maintained she had on many occasions employed people to look after the toddler.
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