The objective of this study was to determine the effect of the main groups of fatty acids, used to make sponge-fatty cakes, on the quality of their crumb. There were developed chemical profiles of eight plant fats and lard. There were evaluated physical and sensory properties of a crumb of products made using the above named fats. The analyzed material constituted fats showing the following differences among themselves: content of the main groups of fats, melting point, and solid phase content. The content of trans isomers in fats studied varied most of all (from 0.2 to 56.7%). Crumbs of the sponge-fatty cakes made had a mass density ranging from 560 to 504 g/dm³, and their compressibility was from 790 to 1189 N/m depending on the fat type used. It was evidenced that trans isomers of non-saturated fatty acids, sums of trans isomers, as well as of saturated fatty acids had a favourable effect on the mass density of the crump of backed cakes. Furthermore, it was stated that the compressibility of crump increased along with the increase in the sum of content of the saturated fatty acids, what was contrary with regard to cis isomers and indispensable non-saturated fatty acids.