Discount retailer Dollar General Corp. (DG) reported strong first-quarter earnings results today that included a 64% jump in profit. Dollar General earnings data also showed that customers visited its nearly 9,000 retail locations more frequently, and that they were spending more per transaction. As a result, after earnings Dollar General also raised its outlook for the full year.

Here are the specifics for DG stock: Net income for Dollar General rose to $136 million, or 39 cents a share, from $83 million or 26 cents a share last year. The Dollar General earnings report showed DG sales grew by 12% to $3.11 billion. Same-store sales were up  6.7%. EPS totaled 42 cents a share, much better than Wall Street’s forecast of 34 cents and totaling a 235 earnings surprise.

Dollar general’s earnings report shows the success of discount chains during the recession. DG stock is trading for just under $30 a share today after rallying on this news, just shy of its 52-week high of $31.41. The stock is up more than 31% year-to-date, compared with a 6% slide in the broader market. DG stock has more than doubled in the last year, compared to a jump of only about 15% or so for the major stock market indexes.

Fellow discounters like 99 Cents Only Stores (NDN), Family Dollar (FDO), Dollar Tree Inc. (DLTR) and Big Lots (BIG) are also faring well. Family Dollar is up about 30% year-to-date and FDO stock actually tallied a positive gain in May as the stock market collapsed. Dollar Tree is up 25% since January 1, and DLTR stock is up about 40% in the last year – three times the broader stock market. Big Lots and 99 Cents Only are both trailing behind that, with BIG stock up about 12% year-to-date and NDN stock up about 3% in the same period, but that is still considerably better than a negative return seen by the Dow Jones and S&P so far in 2010.

Discount retailers have been stocking more fresh foods and increasing both private label and brand name offerings, winning some customers away from bigger retailers including retail king Walmart (WMT), warehouse chain Costco (COST) and cheap chic merchant Target (TGT). Family Dollar earnings are a good sign for discount retailers, and it should be interesting to see how other low-priced retail stores perform in their upcoming quarterly reports.

As of this writing, Jeff Reeves did not own a position in any of the stocks mentioned here.