The objective of this work was to show and verify to what extent it could be possible to reduce ‘trans’ isomers (TFA) in fats used in baking biscuits and puff-pastry cakes, and not to deteriorate their quality. The quality of six (6) fats was evaluated. The fats investigated differed in their composition of acids, in particular in their TFA amount (ranging from 0,1% to 42,3%). There were assessed properties of dough and cakes baked with the use of those 6 fat types. With regard to biscuit cakes, it was stated that when the TFA amount in baking fats was reduced from a level of 42% down to a lower level, the quality of cakes became worse (their volume, porosity of crumb, and sensory values were deteriorated). As for the puffpastry cakes, no deterioration of their texture and sensory quality was found that could be attributed to the reduction of the TFA content in acids from a level of 42% to a level of 27%.