If meatballs are properly stored in a refrigerator, they will last approximately 3 or 4 days. This time period depends upon the temperature of the refrigerator and the freshness of the meat when the meatballs were prepared.
To ensure that meatballs will last for 3 or 4 days, the temperature of the refrigerator should be 40 degrees Fahrenheit or cooler. An air-tight container can help keep refrigerated leftovers tasting fresh.
If stored in a freezer, meatballs can last for 2 to 6 months. The temperature of the freezer should be 0 degrees or colder. Although frozen foods are safe as long as they remain frozen, they are unlikely to maintain their freshness beyond this time period.