I have built eCommerce websites using both Zen cart and Opencart. Both have their plus and minuses. I prefer Opencart because of the ease of use and quick back-end navigation. If you need help to changing from Zen cart to Opencart here is a step by step process that worked for me. The following assumes that the conversion or migration is being done for an online clothing store. While most of the column names in this Zen cart uses the plural form for naming conventions for table names and table fields, Opencart uses the singular. Therefore categories_description becomes category_description, products_to_categories becomes product_to_category. Also, while Zen cart uses the broader description like products_model and products_price, Open cart columns are referred to as model, price, image etc. Also, there are some table fields in Zen cart that are not present in Opencart and thus ignored in the conversion. Log into your database through phpMyAdmin 1. First change elements in categories_description table to category_description table in Opencart (note plural verses singular form) INSERT INTO `category_description` (`category_id`, `language_id`, `name`, `description`) VALUES (1, 1, 'Adult Content T-Shirts', 'adult t-shirts'), (2, 1, 'Children T-Shirts', 'children t-shirts'), (3, 1, 'T-Shirts & Hoodies', 'Regular T-Shirts') 2. Change category table INSERT INTO `category` (`category_id`, `image`, `parent_id`, `sort_order`, `date_added`, `date_modified`, `status`) VALUES (1, NULL, 0, 0, '2011-09-20 15:24:51', '2011-10-03 21:02:26', 1), (2, NULL, 0, 0, '2011-09-20 15:25:14', '2011-09-21 11:20:22', 1), (3, NULL, 0, 0, '2011-09-20 15:25:39', '2012-08-02 06:51:46', 1) 3. Convert the product table INSERT INTO `product` (`product_id`, `model`, `sku`, `upc`, `location`, `quantity`, `stock_status_id`, `image`, `manufacturer_id`, `shipping`, `price`, `points`, `tax_class_id`, `date_available`, `weight`, `weight_class_id`, `length`, `width`, `height`, `length_class_id`, `subtract`, `minimum`, `sort_order`, `status`, `date_added`, `date_modified`, `viewed`) VALUES (28, 'Product 1', '', '', '', 939, 7, 'data/htc_touch_hd_1.jpg', 5, 1, '100.0000', 200, 9, '2009-02-03', '146.40', 2, '0.00', '0.00', '0.00', 1, 1, 1, 0, 1, '2009-02-03 16:06:50', '2011-09-30 01:05:39', 0); Make sure the product "status" field is set to "1" for all products you want to display. 4. Then change products_to_categories table to product_to_category. INSERT INTO `product_to_category` (`product_id`, `category_id`) VALUES (1, 3), (2, 3), (15, 3); 5. Next, change product_description table Remember all plural form of table names should be converted to singular forms and remove the term products in column name INSERT INTO `product_description` (`product_id`, `language_id`, `name`, `description`, `meta_description`, `meta_keyword`) VALUES (1, 1, 'nice shirt', 'really cool shirt.', '', 332); 6. Next, log into your Opencart admin Assign all categories a default or active status. This will ensure that they display on your website menu 7. Then, you will have to cache your images. Zen cart does not cache images into different sizes as Opencart does, so you will have to reload you images into the product image folder for caching This is about it. You will then have to make small changes like options, attributes, banners etc.