In this study, microbiological and chemical changes which occur during ripening of tulum cheese which is traditionally produced from raw sheep milk were studied. Total aerobic plate counts, coliform, Staphylococcus-Micrococcus, Enterococcus, Lactococcus, Lactobacillus-Leuconostoc-Pediococcus, yeast and mould of experimental cheese samples were determined on the 0,15^th,30^th,60^th and 90^th days of ripening period. Furthermore, acidity (as lactic acid),moisture, dry matter, salt, salt contents of dry matter and pH values were determined for the same ripening days.

In all of the samples, total aerobic plate counts which were determined at the beginning stage of ripening increased until the 15^th day and coliform counts until the 30^th day, yeast and mould until the 60^th day, and then decreased with time. The number of Staphylococcus-Micrococcus, Enterococcus and Lactococcus decreased gradually during ripening period and had the lowest level on the 90^th day.

The pH values decreased from curd to 15^th day. However, they increased on the following days. The acidity increased continuously during ripening and had maximum value on the 90^th day. The moisture content decreased during ripening and had remained at low level between the 60^th and 90^th days. Salt concentration in all the samples increased until the 60^th day and decreased later. As a consequence salt amounts of dry matter followed a similar pattern.

It was concluded that; microorganisms which are responsible for spoilage of tulum cheeses increased during ripening and manufacturing and were remained live until the end of ripening, and that traditionally produced cheese was not suitable microbiologically and chemically more studies are therefore needed to improve the quality.