(Adds department stores results, consumer confidence)

MEXICO CITY, Nov 12 (Reuters) - Mexican retailers group ANTAD said on Thursday its members' same-store sales rose 3.0 percent in October compared with the same month a year ago, driven by unusually strong sales from department stores.

An additional Saturday last month, compared with October of 2008, also lifted overall results. Weekends are when Mexicans traditionally shop for goods and groceries.

Department store sales at units that have been open for at least 12 months jumped 10.2 percent in October, as discounts and credit facilities triggered clothing sales ahead of the Christmas season.

Results in this category contrasted sharply with October consumer confidence index, which dropped to its lowest on record, according to Mexico's statistics agency data.

Supermarket same-store sales rose 2.3 percent in October from a year earlier, while specialty store sales slipped 0.4 percent in the same period. (Reporting by Cyntia Barrera Diaz; Editing by James Dalgleish)