Marine litter at the seafloor comprises different materials. Plastic is the most frequent material of marine litter found at the seafloor of the Baltic Sea (55,6%). "Abandoned, lost, discarded or otherwise lost fishing gear" (ALDFG) is a subgroup of plastic litter with special importance for environmental assessment because it has a defined source and may pose a health risk to animals. With the data provided, marine litter at the seafloor of the Baltic Sea was quantified and characterized with special regard to fishery as source. 72 litter items (LI) were collected within fishery catches by bottom trawling during three cruises in 2020 and 2021. The data were used to quantify litter at the seafloor of the Baltic Sea (9.2 LI/km²) including 2.2 LI/km² ALDFG and 0.4 LI/km² fishery nets. We conclude that fishery is an important source of litter and ALDFG represent a considerable share of marine litter with 22.2%.