Social behaviors are crucial for the survival and reproduction. However, little is known about how the brain computes choices when competing stimuli for mutually exclusive behaviors occur simultaneously. Aggression and feeding-related behaviors are regulated by the lateral septum (LS). We previously showed that somatostatin-expressing (Sst) neurons in the LS promote food-seeking (Carus-Cadavieco et al., Nature 2017). Here we investigated functions of the LS, Sst- and neurotensin-expressing (NT) cells, in social and feeding-related behaviors.We combined opto-, chemogenetics and calcium imaging in freely behaving mice to characterize to role of Sst- and NT-expressing cells in social- and feeding related behaviors.Optogenetic activation of NT cells resulted in increased social interaction, accompanied by decreased dominant behavior towards conspecifics. Opto- or chemogenetic activation of NT cells in the LS decreased food intake, also in the absence of conspecifics. Conversely, optogenetic activation of Sst cells in LS decreased social interactions. Upon optostimulation of hippocampal inputs to LS, similar number of NT cells were excited or inhibited. In case of the Sst cell group, majority of cells were inhibited. We also examined the spatial coding by LS-NT and LS-Sst cells. Quantification of the degree of positional activity using field stability and mutual information showed that 20% of LS-Sst cells are place cells.Taken together, our results suggest that Sst- and NT-expressing populations in LS complementary regulate multiple aspects of innate behaviors.Support: Alexander von Humboldt Foundation (to D.K.), ERC Consolidator Grant (772994, FeedHypNet to T.K.) and DFG (SFB1089 and EXC2030-CECAD to T.K., 233886668-GRK1960 to F.S.).