Investigations of glucose and fructose interactions in aqueous mixtures were carried out using near infrared (NIR) spectroscopy and sharing interferometry aided by computer image analysis of analySIS 3.2 software. Spectroscopic measurements involved the analysis of changes occurring in the absorbance spectra within the wavenumber from 4×10³ to 10⁴ cm^-1.The analysis showed that fructose had a strong influence on glucose behaviour in water mixtures. An addition of fructose to a glucose mixture water results in an increase of glucose solubility at the same time decreasing the amount of crystallized solid phase lengthens the crystallization time and finally changes the morphology of the newly-formed crystalline structure. The analysis of the obtained results made it possible to state that in order to predict the effects of glucose crystallization in saturated solutions in the presence of fructose, the coefficient can be used. Negative values of the coefficient will indicate the cases with no tendency for quick crystallization, whereas at values of a tendency for spontaneous nucleation and quick crystallization will be observed. At there is no crystallization at all, at there is a tendency to form star-shaped agglomerates, and at fine crystalline structure is formed. It was also found out that there is a linear correlation between the value of the coefficient and the amount or crystallized solid phase. The verification of the investigations was based mainly on data concerning honey.