Iron is the most common element in nature, and is included among the physiological and active, irreplaceable macroelements. Today, photometric methods are widely used for the determination of toxic and highly toxic heavy metals. This method is of great importance due to its sensitivity, simplicity, and less time spent on analysis. In this article, the optimal conditions for the formation of a complex of Fe(III) with 2-napthylcarboxymethylnitrate reagent were studied and the method of photometric determination of Fe(III) was developed. In the process of photometric determination of Fe (III) with 2-napthylcarboxymethylcitrate, the following was performed: choice of light filter, dependence of complex formation on the acidity of the environment, dependence on the composition of the buffer solution, dependence on the composition of the reagent, field of obedience to Ber's law , spectral characteristics, sensitivity according to Sendal, lower detection limit of Fe(III), molar extinction coefficient, determination of the ratio of component moles of the complex and method of photometric determination of Fe(III).