The winter diet of the great tit (Parus major) was examined in mixed and deciduous forest in central Slovakia during three winters. Using a faecal samples analysis, in 105 sampled roosting individuals (in nest-boxes) at least 37 taxa of invertebrates were found. Apart from the invertebrates, plant material was identified in dissected birds' droppings as well. There were no significant differences in the winter food composition between sexes. Generally, plant material was the most frequent and the most dominant winter food. This component was followed by moths, beetles and dipterans. While comparing the relative volume between two distinct habitats, the most significant difference was found in Lepidoptera adults and plant material. Birds from mixed forest foraged less on Lepidoptera adults in contrast to individuals from deciduous forest. This could be compensated by bigger consumption of seeds and buds there. Regarding seasonal changes, within five winter months (from November to March), the relative volume and frequency of some invertebrate groups (Heteroptera, Homoptera and Lepidoptera) significantly increased with the temperature but no correlations were found with other weather characteristics. Invertebrates exhibited the opposite seasonal pattern compared to the plant material.