The victim, Marianna Manduca, had reported her husband to police 12 times for violence before he killed her.
The murder took place ten years ago in Palagonia, Catania, and the court ruled on Tuesday that prosecutors at the Caltagirone court were guilty of gross negligence and willful misconduct in their handling of Manduca's original complaints.
Manduca told local prosecutors, "He threatened me with a knife, I don't know what I can do any more, please help me", the Repubblica di Palermo reported.
The family's lawyer said the abuse was treated as a "family argument".
Manduca's partner killed her in October 2007, with stab wounds to her chest and abdomen. The killer is currently serving a 20-year jail sentence.
Messina's appeals court ordered the prosecutors to pay €300,000 in compensation to the couple's three children, aged between 12 and 15, who have lived with a relative since Manduca's death.
The family's lawyers said they planned to pursue the case and were only "partially satisfied" by Tuesday's judgment, which recognized only the material damage to the children in terms of their mother's salary, rather than the "moral damage".
However, lawyer Licia D'Amica told La Sicilia: "It's a groundbreaking judgment. Convictions of legal professionals for compensation of damages due to their inertia or errors are extremely rare".
Earlier this year, the European Court of Human Rights ordered Italy to pay a domestic violence victim €40,000 for failing to protect her from her abusive husband, who killed the woman's son and attempted to kill her as well.
That case was hailed as a landmark judgment, with Italy told it had breached human rights and "essentially endorsed" the violence by failing to take seriously the woman's reports of violence.
READ MORE: How can Italy tackle gendered violence?
Photo: Filippo Monteforte/AFP