Predator-prey relationships are an important factor shaping ecological communities. Functional response (FR) describes the relationship between the food resource density and amount of food consumed by a single predator and is commonly used to study the role of predator-prey interactions in population dynamics. Elevated temperature related to global change is likely to modify consumer-resource interactions. Another important factor is predator density, as hunting individuals can be positively or negatively influenced by nearby conspecifics. Higher energy expenditure in elevated temperature requires greater foraging activity (enhancing foraging efficiency), which in turn may increase the competitive pressure between multiple predators and lead to predator interference (reducing foraging efficiency). This underlies the need to include predator density as a factor affecting foraging efficiency when studying effects of rising temperatures. Here, we performed a laboratory experiment using three densities of a fish predator (pumpkinseed, Lepomis gibbosus) (1, 2 and 4 specimens), two temperatures (25 and 28 oC) and 6 prey densities. Using FR approach, we showed the effect of temperature on foraging efficiency of single and 2 predators, but not on foraging of a group of 4 predators. Moreover, increased conspecific presence strongly reduced predator efficiency at a lower temperature, whereas, at a higher temperature, conspecific effect was totally absent (2 individuals) or lower (4 individuals). Our study indicates that predator density is an important factor that should be considered in experiments on the effects of environmental change on foraging efficiency. This research was supported by National Science Centre, Poland (Grant No. 2020/39/D/NZ8/01226)