The present work is part of the project "Hydrothermal Co-liquefaction of microalgae and organic residues". The task was to enable a selection of optimally suited residues for the Co-HTL by carrying out hydrothermal liquefaction experiments. Furthermore, the task was to investigate the influence of inert and reactive atmospheres on the biocrude-yields and -quality. The organic residues were tested for their yield (biocrude, FSP, WP, GP) in a hydrothermal liquefaction reactor. The conditions were 350 °C, 350 bar, 15 min residence time and under argon or mix-gas atmosphere (1,5 % CO, 14 % CO2, 84,5 % N2). The samples and the biocrude were subjected to elemental analysis. Under the Ar-atmosphere, the following average biocrude yields could be achieved: organic waste 16.2 %; green waste 9.4 %; sewage sludge 12.8 %; micelles 34.0 %; food leftovers 35.4 %. The mix-gas atmosphere had the following results: organic waste 14.6 %; green waste 14.7 %; sewage sludge 17.8 %; micelles 42.6 %; food leftovers 26.4 %. The calculated conversion per time was higher in the reactive gas atmosphere. The average calorific value was 35 MJ/kg.