UPDATE 1-Costs, forex dent Mexico Soriana net but revs rise

* Net drops 19 pct in 2nd qtr

* Higher sales costs, forex losses hurt (Adds peso depreciation, costs, revenue, stock quote)

MEXICO CITY, July 28 (Reuters) - Soriana, Mexico's No. 2 retailer, said second-quarter net profit fell 19 percent, hurt by higher sales costs and foreign exchange losses, but revenue increased despite tough competition.

The Monterrey-based company earned 716.6 million pesos ($55 million) in the April-to-June period, down from 883.5 million pesos a year earlier, according to a filing with the Mexican stock exchange on Wednesday.

Mexico's peso retreated more than 4 percent during the second quarter. Higher sales costs during the period, due to aggressive promotions against rivals like Wal-Mart de Mexico (WALMEXV.MX), also dented profit.

Soriana's (SORIANAB.MX) quarterly revenue rose 6.5 percent to 22.82 billion pesos.

The company's stock was little changed at 34.30 pesos at midday. ($1 = 12.94 at end-June) (Reporting by Cyntia Barrera Diaz; editing by John Wallace)