Definitely use a fork!
Oh My goodness, this pizza is the absolute best I have ever had. The atmosphere, the location, good pizza and cold beer make this place my favorite place to have a night out.You have to kind of look for the sign if you don't know where it is, but it is well worth the search.
Recommended: the combination pizza(You'll need a fork!)
Food: 10
Service: 10
Ambiance: 10
Overall: 10
- Definitely use a fork!

good pizza- but get it to go!
This is a very good pie. Deep dish,quality and ample toppings,thick but not doughy crust,sauce flavorful but not too plentiful.The service on the hand was slow and not very pleasant.The waitress spilled my wine in my lap and neither she nor the manager would apologize. My worst service experience ever! Go to their takeout branch.
Recommended: combo pizza
Food: 8
Service: 2
Ambiance: 6
Overall: 2

Nothing better
There's nothing better than Old Chicago Pizza in the entire bay area. I've never been to Chicago so I don't know what Chicago pizza is SUPPOSED to taste like, but if it tastes better than this I'd consider moving there. Frankly I don't know how it could taste better, I've been to Zachary's in Berkeley and even though it's possible that is more "authentic" (I have no way of knowing), Old Chicago is just plain better. I'm a long-time pizza eater, pizza is my favorite food, and my father took us to pizza every friday night as a family tradition we all looked forward to. I strongly recommend the pepperoni and mushroom DOUBLE CRUST pizza, with GARLIC. You can't go wrong, everyone who eats that combo falls in love. The double crust is HUGE, you will do well to eat two slices. The ambience is very VERY cool, it's in a very old building in historic downtown Petaluma, and there are windows overlooking the Mystic Theater and the river. From the wrought iron bars on the windows to the bare brick walls, the ambience is irreplacable. Even the funky red carpet on the way in and the stairway you have to climb (with the cool finger-pointing sign). The building used to be a brothel and it's part of a very interesting "mall" carved out from a labyrinth of halls (called "Lan Mart."). Anyone who tries to say the ambience is bad has got to be kidding... and I don't know about that guy from Chicago, he seems like the kind of guy that would never believe pizza can be made well outside of Chicago.
Recommended: Pepperoni Mushroom and Garlic Double Crust
Food: 10
Service: 8
Ambiance: 10
Overall: 10

Simply the best!
Absolutely fantastic chicago style pizza. Moved from bay area to Austin, Texas and there is nothing even remotely close to this pizza. In fact, I am having an old chicago pizza shipped in dry ice via federal express to Austin. Need I say more?
Recommended: Pizza, pizza, pizza!
Food: 10
Service: 8
Ambiance: 8
Overall: 8

2nd best
As a Chicago native, I'd say that Old Chicago would rate as a decent neighborhood pizza place back home. Still, they do a darn fine crust. They tend to skimp on the sauce, though. Careful eating in during the summer. It's on the 2nd floor, there's no A/C. Better to order pick-up and take it home. Nice 'n cozy in the winter, though.
Food: 6
Service: 6
Ambiance: 2
Overall: 6

Good Stuff!
Old Chicago has been a tradition for me for almost 20 years. The pizza is as great as ever and the restaurant itself has such character inits ambience. I don't know if it really was a brothel, but the mystery makes it a fun place to take out-of-town guests as well as a treat for locals.
Recommended: Pizza, pesto garlic bread
Food: 10
Service: 6
Ambiance: 8
Overall: 8

I live in LA! Old Chicago Pizza is a must stop when I come to town!
Can't get enough. Can't wait can eat there again. It is the best pizza I've ever had!
Food: 10
Service: 8
Ambiance: 10
Overall: 10

I love the pizzas and salads
I love Old Chicago Pizza, and wanted to recommend banana peppers as a topping. I'm thrilled that they have so many vegetarian toppings, and this is the only one they lack. I especially love the lunch specials. The nacho appetizer is wonderful, too.
Recommended: banana peppers (as a pizza topping)
Food: 10
Service: 10
Ambiance: 10
Overall: 10

Don't miss Old Chicago Pizza!!
Old Chicago Pizza is truly the best! Their crust is amazing and the sauce and toppings still make my mouth water. I used to work near this restaurant, and savored my meal each time I went. Don't miss out on this fantastic slice of Chicago! I only wish I still lived in Sonoma County just so I could still eat my favorite pizza in the world!
Recommended: Pesto pizza
Food: 10
Service: 6
Ambiance: 10
Overall: 10

Take-out or take-ouch!
I haven't had their pizza in years! So, we thought that we would try their take-out. I bought one with artichoke and sun-dried tomatoe pesto. After paying the $27+ for a large pizza and returning in the prescribed time, there was a slight name mix-up when trying to find our pizza. Upon opening the box at home I noticed that the pizza was very light on the artichokes so, we added more from our jar at home! I liked the crust. My girlfriend did not think that it was as good as she had had before. I did not think that this was anything great. Maybe the restaurant is better. Maybe I will try another pizza at the take-out store. Maybe it will taste better this morning.
Overall: 4

Deep Dish Baby!
You gotta be kiddin' me? You haven't tried Old Chicago Pizza in Petaluma, CA? What's up with that?! This stuff is better than the pies you get in Chicago. Well, maybe I'm prejudice, living in Petaluma, but it's pretty good. The place itself is cool too: brick walls, windows overlooking the boulevard, a chandelier (fancy!) and it's all housed in a former brothel. How much funkier do you want. Also, don't forget to order a Lisa Iskin salad. They like to say now that it's named after a former waitress, but back in the '80's, they used to say that it's named after a former lady of the night. You choose, but either way, make sure you choose Old Chicago Pizza. You won't be disappointed.
Recommended: Pizza! Also, Lisa Iskin Salad
Food: 8
Service: 8
Ambiance: 10
Overall: 8