BACKGROUND AND AIMS: The immediacy or delay of a reward affect its perceived value. Here we present a new model of assessing delay discounting in group housed mice. METHODS: A group of animals was implanted subcutaneously with radiofrequency identification chips and placed in a cage equipped with sensors for automatic tracking (IntelliCage Plus). Each of the cage’s corners had 2 drinking bottles accessed through a small compartment that allows only one mouse inside. The effect of the delay was assessed by first allowing mice with free access to water or 0.1% saccharin and then progressively increasing the delay till gate blocking the saccharin bottle raised. RESULTS: In line with expectations, while mice initially showed a 95.4% preference for saccharine it decreased to 50% at 17 s delay and finally to 12% at 55 s delay. In the delay discounting model with 3 types of rewards (saccharin 0.01% or 0.1% and water), initial preference of 0.1% saccharine was 92.4%, an increase in delay to 55 s of access decreased preference to 7.8% and caused an increase of preference of the 0.01% saccharine solution from 3.2% to 64.7%. We tested the effects of tranylcypromine, a monoamine oxygenase inhibitor (3 mg/kg, 3 injections in 48 h intervals), cloccinamox, an opioid receptor antagonist (10 mg/kg, single injection) and ketamine, an NMDA receptor partial antagonist (20 mg/kg, single injection) on delay discounting. Treatment with tranylcypromine led to increase in discounting of the delay, at 17 s the saccharin preference was 51% in the control group but only 4% in drug-treated mice. A similar trend towards increased discounting was observed in case of ketamine, while clocinnamox had no effect. CONCLUSIONS: The main advantages of the new model are the ability to test behaviour in the home cage, during natural activity cycles, no interaction with the experimenter and without food deprivation. Further development of the model may permit testing of social effects on discounting.