Quidsi's six retail sites, including Diapers.com and Soap.com, will officially shut down Wednesday.
All the sites will transition to Amazon.com that day and are currently using "we're moving" banners on the top of each site to alert customers.
Amazon, Quidsi's parent company, bought the company for $545 million in 2011 but said last month it would shut down the business because it didn't turn a profit.
The decision could mean that Amazon has a new interest in frugality after spending heavily to expand online or perhaps that Quidsi simply faced poor financial prospects despite its half-billion-dollar price tag.
A preview of the new landing pages on Amazon.com features a basic layout, directing customers to inventory pages from Amazon.com, Quidsi Retail or other retailers.
Quidsi has operated Diapers.com, Soap.com, Wag.com, Yoyo.com, Casa.com and Beautybar.com.
A frequently asked questions page is available here, offering customers information on the change.