UPDATE: According to a few commenters, Pat & Oscar’s Dressing is no longer sold at Costco. I haven’t had a Costco membership in a few years, so thanks for the comments to let me know! According to Arianna (see comments below), it’s only sold during the month of April, so if you haven’t been able to find it, try to look for it then. But Heather’s post with a reply from Costco states that they won’t be carrying the item any longer. I’m not sure which is correct, so if anyone is still able to buy the dressing in April, please leave another comment to let people know. Thank you! 
I go to Pat & Oscar’s every once in a while just because they have some good salad and great dressing. If you don’t want to pay at least $6.49 to get a salad, you can buy the dressing separately for $3.99 for 16 ounces. You can also buy two 32 oz bottles of Pat & Oscar’s House Dressing at some southern California Costco stores, but I don’t have a Costco membership anymore.
If you do have a Costco membership and want to buy it from there, here are some pics of what you’re looking for:
Sorry for the crappy pics. They were taken with my cell phone.
I think it’s cheaper just to buy a salad at Pat & Oscar’s and then ask them for extra dressing. They’ll usually give you one or two extra containers of it (the containers are 2 ounces each), but sometimes if you’re lucky you’ll get a whole handful. I managed to get 10 ounces of it for free today. Woohoo! If I did have a Costco membership, I’d just get it from there though since it’s a lot cheaper than buying from Pat & Oscar’s and you won’t have to buy a salad if you don’t want to.
Can no longer buy P&O salad dressing at Costco. Bought it for years because it was my favorite, now I’m completely lost. Costco told me they no longer sell their dressing even in the restaurant anymore.
Aww, they don’t sell it anymore? I wouldn’t know since I haven’t had a Costco membership for a long time now, but that’s a bummer. I still always ask for extra dressing every time I go to P&O and get a salad, so I still get plenty of it for free. I’m not sure about them not selling the dressing in the restaurant anymore, but it wouldn’t hurt to ask them. It’s not exactly something they advertise on the menu, but it was there in their system the first & only time I ever bought dressing from the restaurant.
Yes Costco in California still sells the Pat Oscars salad dressing during the month of April but it expires in July. I always stock up and it comes in a 2 pack.
I’ve been requesting P&O dressing for months at Costco. I finally got the response “costco will not be carrying this item any longer, sorry for inconvenience.”