The investigation aimed at assessing the quality and storability of 'Golden Delicious' apples. The experiment was performed in two storage seasons (2006/2007 and 2007/2008). Fruit treated with 1-methylcyclopropene (1-MCP) and untreated fruit were stored at 1°C in normal atmosphere (NA), and in three combinations of controlled atmosphere (CA) with the gaseous composition of CO2:O2 - 1.5:1.5; 3.0:3.0; and 5.0:3.0. Fruit quality was assessed after 2, 4 and 6 months of storage; both immediately after storage and after 7 days of being kept at room temperature. In the experiment a drastic inhibition of the intensity of ethylene production in apples treated with 1 -MCP was noted, regardless of the conditions and the length of storage time. Treating fruit with 1-MCP as well as their storage in controlled atmosphere conditions resulted in higher flesh firmness of apples, both directly after storage and after 7 days at room temperature. In the first 4 months of storage the effect of 1 -MCP treatment on fruit quality was clearly more visible in NA than in CA. With the prolongation of storage time a constant decrease of titratable acidity in apples was observed. The rate of this process was significantly slower in the case of fruits stored in controlled atmosphere than in normal atmosphere. The differences between these storage technologies were even more visible after the shelf life than directly after storage. The post-harvest treatment of apples with 1-MCP, substantially limited the decrease of apple titratable acidity, especially under the NA conditions. Fungal diseases (grey mould rot, bull's eye rot and blue mould rot) occurred mostly on fruits stored in normal atmosphere. Treating apples with 1 -MCP usually decreased the percentage of rotten fruits both directly after storage and after the shelf life period.