Is there a way to disable the Title and Subtitle in Highcharts?

Setting the title text to an empty string is the way to do it.

No space is created for the title in that case:

without text: http://jsfiddle.net/jlbriggs/JVNjs/284/

with text: http://jsfiddle.net/jlbriggs/JVNjs/286/

title:{
    text:''
}

If you want less space than is left in that case, simply set your 'marginTop' to 0

{{edit due to numerous comments:

As pointed out a number of times below, the documentation now states text: null as the method to achieve this.

Either method achieves the desired result.

From the highcharts doc:

text: String The title of the chart. To disable the title, set the text to null. Defaults to Chart title.

fiddle: http://jsfiddle.net/daub10dr/

title:{
      text: null
      }