The objective of the present study was to determine the physical-chemical and microbiological (total micro-organism count) properties of broiler chicken breast muscles stored in a controlled atmosphere (95% nitrogen, 5% oxygen) at 2°C during a period from 5 to 25 days. The samples investigated were breast muscles both wrapped in a Nordfilm–Nordform packing and unpacked. On the basis of the investigation results it was proved that the pH value of meat increased gradually, and its colour became darker and darker as the time of cold-storage was prolonged. These undesirable changes in the meat quality proceeded slower in the packed samples than in unpacked. Similar regularities were stated during the development of the intramuscular lipids stability determined on the basis of acid number. According to the results of microbiological analysis and assessment of breast muscles, based on the total microorganisms count per one gram, it was confirmed that the level of microbial contamination was satisfactory in packed samples stored 20 days under the controlled atmosphere, and, also, in unpacked samples stored during a period of 15 days.