Ida is the mother of Lois and Susan. She is an immigrant from an unnamed country she refers to as 'the old country' but it is highly implied that she and her husband are from Croatia, due to the Croatian flag and a picture of the Zagreb cathedral in the background of the episode "Ida's Dance"
She is the only person in the entire series that is potentially more sadistic and cruel than Lois, possibly the cause of both her daughters timidness in her early life and her hardened personality of today. Ida gave her daughters an incredibly strict bordering on cruel upbringing, forcing them to do things they didn't want to and inflicting punishments on them that were far worse than what Lois has ever done to her sons. Yet she shows favoritism to Susan because she rose above the challenge with grace and talent. Ida continued to treat Lois with so much contempt, even blaming her for ruining Susan's life by stealing Hal from her and marrying him for herself.
Even in recent years she has no problem taking advantage of her family, telling the police that she is the owner of the family house and Francis and a pregnant Lois were imposing on her. Yet, she was foiled by the boys when they came together and sent her on her way home.
Out of the boys, Ida strongly loathes Francis the most and their feud is ongoing. This evident when she called him as a child to wish him a Merry Christmas and he responded by calling her "Poopy", along the other problems she had to deal with when he was living with her. Ida does have one thing in common with Francis, they both hate Lois for being a control freak revealed in Ida Loses a Leg. Ida shows blatant favouritism towards Reese, since he is the strongest of the three younger brothers and seems to follow her wishes well. While at the same she openly dislikes Malcolm because he is not as strong as Reese and actually 'dares' stand up to her and question her traditions. She also believes that Reese is the smart one and Malcolm is the stupid one (she also thinks that Malcolm is homosexual). Another reason why Ida thinks Malcolm is weak is because he doesn't stand up to Lois and shows contempt for him when he refuses to do so.
One of the greatest examples of her evil and dispecable nature, was she drugged a wealthy Chinese man, Mr. Wong, into marrying her with powerful drugs that made him constantly happy(even around her!!!). When Malcolm discovered her plan and told Lois about it, he couldn't say anything with an "S" because of his botched tongue piercing. Furious she and Hal tried to stop Ida, but she got them drugged and happy(including baby Jamie). However this proved to be her undoing because she used all the drugs on Lois and her family, that Ida was unaware that the Priest got a hold of the last of the drugs and used it on himself so he can fall in love with her much to her detest. Mr. Wong came out of it just in time and ran off after seeing her for the greedy person she is. Despite this, it is also revealed that she is an enormous bigot, showing a fear of black people (the family later uses this fear to try and get her out of the house when Lois is pregnant), and open contempt for Francis' wife Piama, an Inuit
Ida has lied to Lois her whole life (Victor wasn't her real father, Susan is only her half-sister with him), which her lies finally came to light in "Victor's Secret Family". The only time she was close to showing Lois actual love was when she was helping her with an upcoming case against Sylvia and encouraged Ida to improve her manners. However, Lois soon discovered the truth that Victor wasn't her biological father and that Ida was involved with a man named Radu Gogorsky whom was her real father. Furious upon being lied to, she willingly abandoned Ida's case and fled with her boys back to California. Ironically, she saved Dewey from getting run over by a truck at the cost of her leg. However, it does not change her demeanor nor the family's hatred of her. This is evident in "Ida Loses a Leg" when Ida demanded that he repays her for saving his life by being her caretaker, though Lois abrasively refused and insisted on Francis because he doesn't have a job(while Reese and Malcolm both have jobs and Dewey's going to school). She is last seen in the episode "Graduation," during which she intended to help Reese with his plot to stay janitor at his school.