The Pediatric Intensive Care Unit is a multidisciplinary unit that provides care for infants, children and adolescents who become critically ill or injured. Admission of a child to the Pediatric Intensive Care Unit is a stressful situation for the mothers who are accompanying them in PICU. It is very difficult to explain the devastating stress experienced by mothers. Aim & objective: The aim of the study is to assess the level of stress, the qualitative experience of stress and its association with selected demographic variables. Methods: The study has adopted Mixed Method Research design and was conducted in PICU K IGMC& Hospital, Shimla. A total of 32 (total enumeration) and 9 mothers (purposive) were taken respectively for quantitative and qualitative interview. A semi-structured interview schedule, Perceived Stress Scale and Qualitative interview were used for data collection. Results: Data analysis was done by using the descriptive, inferential statistics, Colaizzi’s steps and by mixing of data. The study results reveal 6 (18.8) of mothers had high and 26 (81.3) had a severe level of stress. The type of family, family budget alters due to the illness of child were found to have a strong association at 0.05 level of significance. The causes of stress, the impact of stress, predominant thoughts/feelings, adaptive thoughts and behaviors, perception about medical care/ health care professionals, information needs and perception of support system emerged as the main themes of the qualitative study. In mixing the quality of stress is explored in the forms of the impact of stress and cause of stress etc. has clearly supported the level of stress among mothers. Conclusion: The results of the study show that mothers are highly stressed due to the child’s admission in PICU. So its emphasis on the use of coping strategies, grievance and counselling cells in the hospital.