Samples of nanocrystalline iron, promoted with hardly reducible oxides (Al2O3, CaO, K2O), with different average nanocrystallite sizes (20–35nm) and different distributions of sizes were subjected to magnetization measurements. The measurements in 4–300K range in field-cooled and zero-field-cooled modes and isothermal (at 2K and 300K) magnetization in magnetic fields up to 70kOe of these samples provided many magnetic characteristics that have been correlated with very complex samples morphologies. Additional magnetic properties of the investigated nanocrystalline material were obtained by studying the ferromagnetic resonance spectra taken at room temperature. The spectra were decomposed on dysonian components and analyzed in terms of different possible magnetic structures that might be responsible for their appearance. The complex morphology and strong interparticle interactions seem to be the main factors that determine the magnetic characteristics of the analyzed samples.