Wrap floated elements within a container with clear fixed:

html
<!-- html -->
<div class="cf">
    <div class="flt-lft">Float left</div>
    <div class="flt-rght">Float right</div>
</div>
css
/* css */
.cf:before, .cf:after { content: " ";  display: table; }
.cf:after { clear: both; }