Do you really need a degree in Computer Science to get hired by a big software company?

http://norvig.com/21-days.html (Peter Norvig, Director of Research @Google): If you want, put in four years at a college (or more at a graduate school). This will give you access to some jobs that require credentials, and it will give you a deeper understanding of the field, but if you don't enjoy school, you can (with some dedication) get similar experience on your own or on the job. In any case, book learning alone won't be enough. "Computer science education cannot make anybody an expert programmer any more than studying brushes and pigment can make somebody an expert painter" says Eric Raymond, author of The New Hacker's Dictionary. One of the best programmers I ever hired had only a High School degree; he's produced a lot of great software, has his own news group, and made enough in stock options to buy his own nightclub.

In 35 years, I've worked with all sorts. When I was in college, there was no such thing as computer science. The scientists programmed their computers, the engineers theirs, and accounting was usually in control of the rest.   It really comes down to the personality of the company. And, like humans, those personalities cover the spectrum of demands and expectations.   In my early years, on the job training was typical. Not these days.   If you are good enough, you'll get work.

A lawyer needs to go to law school and pass the bar to be a practicing lawyer.  A software engineer doesn't have pre-requisites like that.  If you have the ability to produce results and can show it, you'll get hired.  I have worked with people who majored in Physics, Mechanical Engineering, Chemical Engineering, etc.  They learned the concepts needed on their own and then practiced their skills in writing code on their own.  They have ended up being very good and successful engineers.

In order to answer this question I feel the need to define 'job at Big Companies'. I have been working with one of the companies defined here in the question as Software Development Engineer. Typically such companies have very high users to developer ratio. Facebook probably has a million users to a developer kind-of ratio. Now, when one is pursuing a job opportunity with such companies certainly some skill-set are 'must have' in the candidates. These could be, academic knowledge, problem solving skills, overall liking (and ability) to code the functionality, and – above all – one very important thing, ability to quickly grasp the organizational needs, team-level needs and product needs. In order to be able to create a well glued environment among peers, other team members, leads and – at times – subordinates, skills play a key role. A degree in Computer Science is one such yardstick to make sure that the candidate being hired is able to 'talk' and 'understand' the language spoken in the company thanks to the rigorous course work one passes during undergrad / grad / doctorate study. However, this (i.e. degree) is mere an initial gate-keeper to separate the candidates with inclination towards to computer from the rest. In this process, sometimes, 'injustice' or rather mis-judgement could happen. (There are umpteen examples in the valley who were denied job and later on they went on becoming success entrepreneurs. Or sometimes students themselves did not opt for job in big companies in order to start their own however small.). All in all, I believe, (1) Degree is an initial check and assumption of liking and ability (2) Big companies need people whoa re already equipped with some basic quality and process understanding (so as they need to spend less resources to 'train' the new grads) (3) One can be successful without degree IF s/he has strong liking in the computer programming and the same is true otherway round for degree holders without keen interest.

Nope. But, as in all cases of not going to school, success stories are more often the exception than the rule. By not going, you put yourself at a supreme disadvantage to those that did attend.

For mechanical and electrical engineers, you can get hired by large companies without an engineering degree.  But many times, your career advancement within the technical field at the company is limited without an undergraduate (or sometimes even a graduate) degree in engineering.  But computer science may be completely different.  

No, but it REALLY REALLY helps. When I see two resumes, one with a CS degree, and one without, I strongly favor the one with the CS degree. Generally, here's how I rank specifically the education sections of resumes: By degree type. CS preferred, a degree in Software Engineering is just as good. EE or EECS a close second, but I really value strong OO Design skills, that the low level guys often trivialize. The country in which they got their degree. Preference order: US/Canada/Europe. It is common for somebody to get their undergrad CS degree in India, then come to the US and get a masters, jsut to have a US CS degree on record. This is great, and works for me. School reputation. I consider all the top US news top 100 to be in the same boat. The top 5, especially Stanford, will get extra brownie points with me. As for the other 95 in that top 100, I'll consider them equivalent, and let them differentiate themselves in other ways (like experience, "cultural fit", etc). Degree level. Very often the best candidates are those with just a bachelors degree -- they were hot stuff out of college so landed a great career, and kept landing more without ever needing to get a masters+. That being said, a masters is great too, of course. Certifications. These help only if they're directly applicable. If they don't have a CS degree, but have one in like Art, I'll drill them harder to make sure they can code well. Again, I like to focus on OO Design. Sometimes you find a guy that dropped out of his bachelors degree program because there were just amazing opportunities for him in the industry (like at Facebook), I'll certainly give a guy like that "credit" for having a degree in my mind. I will, however, drill him hard on experience and cultural fit. Guys like this can have a problem with completing stuff... it really depends, so I need to screen for that. I'm assuming you are talking about getting hired as a software engineer.

In short you don't need a degree, I work in a small team and i look for indications of autonomy, creativity and dedication. Experience is what breaks ties.