Will I lose my domain name if I shift web hosting from one company to another?

This question is generally put forward by people who have bought the domain name and web hosting together. There may be different reasons why you are thinking of a web host change. The present hosting package might be expensive or you may be dissatisfied with the customer support. In any case, rest assured (unless you have been dealing with a really bad web hosting company), you will retain your domain name.

Domain name and web hosting are different entities

Even though the company would have billed you together, a domain name and a web hosting package are different entities. A domain name is just a name - like the name of your company. Web hosting is the hard disk space that you take on rent on a web hosting server. So extending the analogy of a company, web hosting can be regarded as the rented office through which you run your business. You can change your office anytime you like... right? Similarly, you can change web hosts without a problem and keep the domain name.

Checking whether the domain name belongs to you

The first thing I recommend to anyone who wants to change their web hosting server is to confirm if the domain name is indeed in their name. The best way to do this is through the WHOIS service. Click on the link below to be taken to NetworkSolutions, go to the WHOIS section (a link to which will be at the very bottom of the page) and enter your domain name to get the WHOIS results.
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What you should look out for are the contacts of your domain name. Each domain name has three contacts - Administrative contact, Billing Contact and Technical contact. It is important that your name and email appears for the Administrative contact. Make sure that your postal address associated with the domain name is correct and the email address is still in use.

Once you confirm that the domain is yours you can freely change the web hosting package.

NOTE: I have heard of unscrupulous companies that did not put the domain name on the customer's name. If you are facing this situation, you have the right to the domain name because you have paid for it! Fight it out with the company... they would generally relent.

So in short, you would NOT lose your domain name when you change web hosting - as long as the Administrative contact of the domain is in your name.

For further details, refer I'm not happy with my present web hosting. Can I change it?. Step-by-step instructions can be found at - How do I change my web hosting server?.