Wal-Mart Stores Inc has reported that June same store sales rose 5.8 percent, beating forecasts.
Analysts had expected a rise of 3.8 percent.
The discount retailer posted strong results in grocery, entertainment and health and wellness.
It attributed the performance to favourable weather and improved assortments, which helped drive seasonal sales in apparel, toys and hardlines.
Total sales rose to US$39.9 billion, up 11.5 percent on last year.
Executive vice president and chief financial officer Tom Schoewe has estimated that US same store sales for July will be between two and four percent.