I have a Mac with OS X 10.4. How can I upgrade to 10.5?

Welcome to the Apple Support Communities

See if your computer is supported > http://support.apple.com/kb/sp575 Buy Snow Leopard > http://store.apple.com/us/product/MC573/mac-os-x-106-snow-leopard Then, make a backup, insert the disc and upgrade. Finally, go to  > Software Update and install the most recent version.

Open App Store and purchase Mountain Lion. Check if your Mac is supported > http://www.roaringapps.com

Mac OS X 10.5 "Leopard" is available from retailers such as Amazon for slightly less than a King's ransom.

Lalaso Perez wrote:

... Is there a way to do it online?

No.

If you have an Intel Mac (as opposed to a PowerPC) you can probably upgrade to Mac OS X 10.6 "Snow Leopard" for only $20.

To determine what kind of Mac you have,  > About this Mac...

There is no "download" version of Leopard (10.5). Anyone who says they have one is giving you a copy of a single-use license. That is illegal and we could not help you with it because of the violation of the license. You also would receive "modifications" they add to report your activities to their central server (eek!).

Legal disks cost around $200 on ebay or amazon.

Requirements for Leopard:

If you have an Intel processor, you can go to SL for about $19 instead of $200.

You can buy Snow Leopard instead, so you'll save money and you'll use a later OS X

As mende1 said ... use this link, and make a very good backup: http://store.apple.com/us/product/MC573/mac-os-x-106-snow-leopard

Some report that going all the way from Tiger to SL as an "upgrade" does not work always, so sometimes you need to "clean install" SL and "migrate" settings and users from a previous backup.

You're welcome

Lalaso Perez wrote:

I do have an Intel processor. I will purchase Leopard.

Not Leopard... Snow Leopard! There is a difference.

Apple did not make it easy by giving them similar names.

Purchase it here:

Online (US):

http://store.apple.com/us/product/MC573/mac-os-x-106-snow-leopard

Online (UK):

http://store.apple.com/uk/product/MC573/mac-os-x-106-snow-leopard

Elsewhere: call the phone number in the Apple Online Store