Reducing the fat and/or sugar content in biscuits can be a way to improve their nutritional composition. Seventy-nine consumers of biscuits were recruited to study the impact of these reductions on liking and perception. Four categories of products were selected from a wide range of biscuits available at the French market. Three to six variants of each type of biscuit were produced based on reduced content of sugar, fat or both. Consumers tested the samples under laboratory conditions (6 sessions), recording their liking during initial sessions and crispiness, sweetness and fat perception during latter sessions. Sugar-reduced biscuits were perceived as less sweet than standard biscuits at low reduction levels, whereas fat-reduced biscuits were perceived as less fatty than standard biscuits at higher reduction levels (except for one biscuit among the three biscuits studied). A reduction in the sugar content had no effect on perception of fat, whereas a reduction in the fat content sometimes induced a reduced sweetness perception. For most of the biscuits studied, the least appreciated variants were those perceived as (1) less sweet, (2) less sweet and less fatty or (3) less sweet and less crispy than standard biscuits. Moreover, the variants only perceived as less fatty were not significantly disliked. These results suggest that from a sensory point of view, it is more acceptable to reduce the fat than the sugar content in biscuits, at least when products are not perceived as being less sweet.