<p>I have this solution for a single button:</p>

<pre><code>myButton.Attributes.Add("onclick", "this.disabled=true;" + GetPostBackEventReference(myButton).ToString());
</code></pre>

<p>Which works pretty well for one button, any ideas on how to expand this to 2 buttons?</p>

You could add an clientside onSubmit handler, or you could do this:
```
```
myButton.Attributes.Add("onclick", "this.disabled=true; document.getElementById('" 
+ button2.ClientID + "').disabled = true;" 
+ GetPostBackEventReference(myButton).ToString());
```
```