Here, we examine whether neurons differentiated from transplanted stem cells can integrate into the host neural network and function in awake animals, a goal of transplanted stem cell therapy in the brain. We have developed a technique in which a small “hole” is created in the inferior colliculus (IC) of rhesus monkeys, then stem cells are transplanted in situ to allow for investigation of their integration into the auditory neural network. We found that some transplanted cells differentiated into mature neurons and formed synaptic input/output connections with the host neurons. In addition, c-Fos expression increased significantly in the cells after acoustic stimulation, and multichannel recordings indicated IC specific tuning activities in response to auditory stimulation. These results suggest that the transplanted cells have the potential to functionally integrate into the host neural network. Display omitted •Stem cells were transplanted into the inferior colliculus (IC) of rhesus monkeys•Differentiated neurons formed reciprocal anatomical connections with host neurons•Some differentiated neurons responded to auditory stimuli in an IC-specific manner•Transplanted stem cells likely integrated into host neural networks Integration of differentiated neurons into a functioning neural network is important for the development of stem cell therapies. Wang et al. found that neurons differentiated from transplanted stem cells respond to auditory stimuli in awake monkeys after transplantation.