A new species of nonstarter lactic acid bacteria (NSLAB), called Lactobacillus wasatchii WDC04, was identified in aged Cheddar cheese manufactured in northern Utah. This bacterium has been linked to gas formation in the latter stages of Cheddar cheese ripening. It is an obligate heterofermentative NSLAB shown to produce gas in broth cultures under the conditions of cheese aging. WDC04 prefers growth on ribose at low pH (5.0–5.5). It grows slowly at cold temperatures, which could play a role in its ability to create gas defects during cheese ripening. In aging cheese, gas formation causes swelling of the packaging and splitting of the cheese, making it unfit for consumer use. Twenty-seven aged Cheddar cheeses from around the world were tested for WDC04 using MRS medium (pH 5.2) amended with 1.5% ribose and incubated for 1 to 4 weeks. Isolates were identified using 16S rRNA gene sequencing then compared with the GenBank database and to the 16S rRNA gene from Lb. wasatchii WDC04. No Lb. wasatchii were detected in cheeses without gas defects. WDC04 was found, however, in several distinct aged commercial Cheddar cheeses produced in facilities geographically distant from the original isolation location. These results indicate Lb. wasatchii is more widespread than previously thought, and appears to be a causative agent of late gas defect in aged Cheddar cheeses.