If font size in the figures do not change in Matlab..

If you wish to change the font of the text in your Matlab figure globally, then you have to set :

>>set(gca, 'FontSize', xx);

And if you want to change it only for a specific legend or text or axis-handles just add the option 'FontSize',  xx  to your parameters.

But this did not work in my Ubuntu 12.04 system. No matter what changes I made, Matlab displayed a fixed font size.

Thanks to the following forums, I could sort it out:
 
 
http://www.mathworks.in/matlabcentral/newsreader/view_thread/301184
http://ubuntuforums.org/showthread.php?t=1762805

You need to go to terminal and install following two packages, log in again.
 
$sudo apt-get install xfonts-75dpi
$sudo apt-get install xfonts-100dpi