Emitter clogging is one of the most important factors that affect the performances on drip irrigation systems. Emitter clogging, which is formed in a short time due to irrigation systems' running under an inadequate pressure or owing to water quality, not only negatively influences uniformity of water distribution but also causes inadequate irrigation. In this survey, the clogging level determination of the emitters used in drip irrigation systems of some agricultural farms situated in Canakkale and their effects on irrigation performances were observed. The emitters were obtained from different farms in the investigated area, and were tested under the pressures of 50, 100, 150, 200, 250, 300 kPa in hydraulic laboratories. The clogging extend of emitters, flushing of clogging increased pressure and also performance values as coefficient of variation (Cv) under 100 kPa pressure, statistical uniformity (Us), emission uniformity (Eu) and Christiansen's uniformity coefficient (Cu) were established through the tests. Acquired performance values must be matched with emitter performances that have not been used in irrigation. As a result of the study it was determined that some emitters are plugged on laterals used for 2 or 3 years in consequence of the tests. It as also determined that emitter coefficient of variation varied in the ranges of 0.43 and 0.63, 0.43 and 0.69, 0.48 and 0.58, 0.56 and 0.73 for unused emitters, for one year, for two years and for three years used emitters. Coefficient of variation between emitter flows remained within the limit of 5% in all laterals, except for one of the laterals used for one year. Coefficient of variation of emitters along two of the laterals used two years and all of those used three years remained out of 5% limitation. Similar results to CVm (manufacturing variation coefficient) were determined for performance parameters in respect of statistical uniformity (Us), emission uniformity (Eu) and Christiansen's uniformity coefficient (Cu).