This study was conducted between 2001-2012 to determine the suitability of nitrogen fertilizers used in Turkey to the country`s related standards and regulations. Totally 5111 analysis were made using 1745 fertilizer samples covering almost all regions of Turkey and their nitrogen and nitrogen form contents and some physical properties were determined. Evaluations were made separately for each year, additionally twelve years average and total values were calculated.

According to results of the analyses, nitrogen fertilizers did not contradict with related standards and regulations. Although a very few fertilizer samples taken in some years were found unsuitable with reference to standards and regulations as of one or two characteristics, suitability rates were found to rise dramatically in recent years. When an evaluation was made among all the parameters considering the results of twelve years, moisture was leading with the suitability rate of 99.5 % and free acidity has brought up the rear with the suitability rate of 90.0 %. Average suitability rate was calculated as 92.0 % when total numbers of analysis were considered.