In this study, the performance and structural properties of single jersey fabrics are investigated. The yams, Ne 30/1 and 20/1 which are commonly used in production of these fabrics in Turkey, made of a 100% cotton open-end spun yams manufactured under the same conditions using the same fibres. The fibre characteristics evaluated by HVI-900, a fibre testing system, are given in the material section of the paper. The performance and structural properties were determined as the fabric weight, the dimensional stability and other structural parameters, spirality, bursting strength, and pilling tendency. It was aimed to perform the test in two ways. Testing the fabrics before any treatments just as knitted and taken them up from the machine. In the second case, they were tested after the sanforization process applied on the same fabrics.