Introduction: Anything which threatens homeostasis is called stress. Stress can be physical, psychological or emotional. Changes in brain is called neuronal plasticity which can be structural or functional. Aim: To study the dendritic branches and their lengths of pyramidal neurons in Hippocampus of wistar rats after immobilized stress. Materials and Methods: This experimental study was performed at College of medicine, NAIHS, Kathmandu, Nepal from August 2021 to February 2022. Sixteen female Wistar rats of different age group consisting both of control and experimental were chosen. They underwentimmobilized stress. At the end of stress protocol, rats were sacrificed and hippocampus was taken out and staining procedure were performed. Confocal microscope was used to obtain images of neurons. IMARIS software was for neuronal reconstruction. The different parameters of apical and basal dendrites of both control and experimental rats were compared using unpaired t-test. The data were compared with Microsoft Excel worksheet (Microsoft office professional plus 2013 version). Results: It was found that all the apical dendritic parameters (principle dendrite’s length, branch points & branch length) in group A were shrunk and the changes were significant (<0.000217, <0.027854 &<0.001). It was also found in group A that all the basal dendritic parameters (number, branch length & branch point) were diminished too but the changes were not significant (<0.842873,<0.156947 &<0.180474).In group B, all apical dendritic parameters (principal dendrite’s length, branch point & branch length) were shrunk too and the shrinkage was also significant (<0.007705, <0.000423 &<0.007811). All the basal parameters in group B have decreased except branch lengths but the differences were not significant (<0.743144,<0.364572 &<0.507876). Conclusion: Immobilized stress causes significant atrophy in apical dendrite parameters of pyramidal neurons while the changes of basal dendritic parameters were not significant in hippocampus of rats aged between 3 to 11 weeks.