These instructions relate to the default theme of OpenCart but should work for any theme provided you change the default bit with the themes name!

Open: catalog/controller/product/category.php

Find (Line 329):

if (file_exists(DIR_TEMPLATE . $this->config->get('config_template') . '/template/product/category.tpl')) {
$this->template = $this->config->get('config_template') . '/template/product/category.tpl';
} else {
$this->template = 'default/template/product/category.tpl';
}

Replace With:

//start custom category design by ItsAdam.co.uk
if (file_exists(DIR_TEMPLATE . $this->config->get('config_template') . '/template/product/category.tpl')) {
if ($category_id == 1) { //Category 1
$this->template = $this->config->get('config_template') . '/template/product/category1.tpl';
} elseif ($category_id == 2) { //Category 2
$this->template = $this->config->get('config_template') . '/template/product/category2.tpl';
} elseif ($category_id == 3) { //Category 3
$this->template = $this->config->get('config_template') . '/template/product/category3.tpl';
} elseif ($category_id == 4) { //Category 4
$this->template = $this->config->get('config_template') . '/template/product/category4.tpl';
} else { //default
$this->template = $this->config->get('config_template') . '/template/product/category.tpl';
}
} else {
$this->template = 'default/template/product/category.tpl';
}
//end custom category design

For our new custom categories we will need to create the templates so that they're viewable and custom.

Find: catalog/view/theme/product/category.tpl

And duplicate it and name it inline with the naming in the above code, ie category1.tpl etc etc

This OpenCart Mod is published for free to the Community, if you require more extensive modifications or OpenCart Themes, contact Dijitul.com who specialise in OpenCart 1.5 Theme Design.