I discovered that if the text size in IE8 is set at "normal", my site behaves as I would expect. However, increase it to "larger" and it pushes the left floated sidebar into the centre. Any ideas as to how I cure this problem. (I am a Mac user, and this doers not happen with Firefox, Safari, Chrome or Opera). I am in the process of installing IE7 on to an ageing lap top PC to see if the same thing occurs, but haven't got there yet. My CSS (the relevant parts) is as follows: body{ margin:0; padding:0; text-align:center; color:#000000; font-family:"Lucida Grande", Verdana, sans-serif;font-size:62.5%; background-image:url(../images/grey.gif)} h1{font-size:2.0em;font-style:normal;font-weight:bold;text-transform:uppercase;letter-spacing:4px;color:#0000FF;height:auto;text-align:center;} h2{font-size:1.8em;color:#996600;} h3{font-size:1.7em;color:#993300;padding-bottom:10px;} h4{font-size:1.5em;} h5{font-size:1.3em;font-style:normal;color:#333333;} h6{font-size:1.0em;color:#FFFF33} p{font-size:1.3em;text-align:left;font-weight:normal;color:#333333;} .bluebold{color:#0000FF;font-weight:bold;} .italic{font-style:italic;color:#CC00FF;} .linktext{font-size:1.0em;} .grey{color:#999999;font-size:1.0em;} #container{width:950px;text-align:left;font-family:"Lucida Grande", Verdana, sans-serif;margin-right:auto;margin-bottom:0;margin-left:auto;background-color:#FFFFcc;border-top-width:0px;border-right-width:1px;border-bottom-width:1px;border-left-width:1px;font-weight:bold;} #header{background-color:#FFFFcc;text-align:center;padding-right:10px;padding-left:10px;margin-top:10px;margin-right:111px;margin-bottom:10px;margin-left:10px;} #sidebar1{float:left;width:120px;margin-top:15px;margin-right:10px;margin-bottom:10px;margin-left:10px;padding-top:15px;padding-right:10px;padding-bottom:15px;padding-left:5px;} #sidebar2{float:right;width:200px;height:800px;border-left-color:#0033FF;border-left-width:thin;border-left-style:dotted;background-color:#e8e8e8;background-repeat:no-repeat;margin-left:5px;padding-left:10px;padding-right:10px;margin-top:15px;text-align:center;} #mainContent{background-image:url(../images/Rugby3-2nobg.jpg);background-repeat:no-repeat;margin:0 0 0 150px;padding-top:0;padding-right:20px;padding-bottom:0;padding-left:20px;} #listings{background-color:#ffffcc;text-align:left;padding-right:10px;padding-left:10px;margin-left:15px;margin-right:15px;height:590px;overflow:auto;} * * * My home page uses the #mainContent as the main box. All remaining pages use #listings as the main box. The centring of sidebar1 with IE8 happens on all pages when set to "larger" type. Any and all advice/help greatly appreciated. Dominic