The retailer's new saliva test can only be bought online.
Because it's a spit test, you don't have to worry about a long nasal swab.
The process is pretty simple: Order the test, do it yourself at home and mail it back in.
It takes anywhere from 24 to 72 hours to get your results and costs between $130 to $140.
Does Costco's new at-home COVID-19 test really work? Medical expert reacts
Results from the PCR test are provided online through an app by the company AZOVA that is billed as being HIPAA-secure.
A medical expert who is familiar with various coronavirus testing methods said the one offered by Costco is believed to be quite effective.
Bay Area-based Dr. Alok Patel noted the saliva test is easier than putting a swab up your nose and the results come back faster than many other testing methods.
When tested head-to-head, he said, the Costco saliva testing kit detected just as many, if not more COVID-19 cases than a different, traditional, PCR nasal swab test.
The Costco tests are "about 99 percent sensitive, 98 percent specific. In other words, you can say the positive tests are positive, and the negative tests are truly negative," Dr. Patel said.
"This is an accurate test."