General principles of magnetite iron quantitative phase analysis in ores of variable composition are considered. Major characteristics of the developed methods of magnetic-chemical and magnetometric analyses are noted. The results of magnetite iron content analysis in ores and their processing products, obtained by means of these methods, are presented with regard to different iron ore deposits of Russia and Kazakhstan. Main advantages of the developed magnetic-chemical method of analysis, as well as the peculiarities of the magnetometric analysis method application with Satmagan magnetic materials analyzer, are described. Recommendations are given with respect to sample preparation for analysis and magnetite iron content quantitative magnetic-chemical and magnetometric analyses methods application.