Drain liquid from the beets into saucepan. Place beets, onions, and eggs into a large bowl or pitcher.
Pour sugar and vinegar into the saucepan with the beet liquid and bring the mixture to a boil. Reduce the heat to low, and let the mixture simmer 15 minutes.
Pour the beet juice mixture over the beets, eggs, and onions. Seal the bowl or pitcher and refrigerate. Refrigerate for at least one to 3 days; the longer they are allowed to sit the better they will taste.
