Abstract: An open front refrigerated display case having an improved ambient air defrost system which includes a housing with a display compartment area for displaying articles therein and an open front area to facilitate placement and removal of the articles, a main refrigeration duct extends throughout the housing having a primary inlet above the open front area and a primary outlet defined below the front area, a primary refrigeration coil is positioned within the primary refrigeration duct for cooling of air passing therethrough and a primary fan device is positioned within the primary refrigeration duct to facilitate drawing of air through the air inlet and expelling of refrigerated air through the air outlet in such a manner as to form an air curtain across the open front area. An ambient air defrost system is included having an ambient air circulation device such as a fan and an ambient air drive means for powering thereof.