Introduction: Pneumonia and diarrhoea are amongst the most common causes for hospital admission for children in low- and middle-income countries such as Bangladesh. Undernourished children often have more severe infections and a higher morbidity and mortality. Objective: The objective of this study was to determine the clinical features and outcomes of pneumonia in severely malnourished children with and without diarrhoea. Methodology: A retrospective chart analysis was carried out on children under 5 years of age who were admitted in intensive care unit of the Dhaka hospital of International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b). A total of 245 severe acute malnourished children with pneumonia and diarrhoea (PD group) were compared with 89 children with pneumonia only (PO group). Results: A significantly higher number of children from the PD group had some/severe dehydration (16.3% vs. 1.1%; p 0.005) when compared with children from the PO group. The PD group showed less cough (83.3% vs. 100%; p 0.001), lower chest wall indrawing (40.4% vs. 60.7%; p = 0.001), and crackles (62.4% vs. 87.6%; p 0.001) compared to the PO group at the time of admission. Conclusion: Early diagnosis and treatment of some/severe dehydration in addition to WHO recommended other routine treatment of diarrhoea, pneumonia and severe acute malnutrition in children may help to reduce childhood morbidity and mortality especially in low- and middle-income countries.