Background Acute lower respiratory tract infections (ALRTIs) are a leading cause of morbidity and mortality in infants in low- and middle-income countries. We emphasize the differences in presentation and outcome between viral and bacterial origin community acquired ALRTI in late neonatal period. Methods All consecutively admitted neonates, aged 7 days or older, with features of ALRTI were included in the study, other than babies referred with prior hospital stay, congenital airway malformations and heart disease. Relevant investigations including nasopharyngeal swab polymerase chain reaction (PCR) and blood culture were done for etiological diagnosis. The predisposing factors, presenting features and short-term outcomes were compared between viral and bacterial etiology cohorts. Results Half of the 89 babies had primary viral infections, respiratory syncytial virus (RSV) being predominant (n = 21, 23.6%); 27 (30.3%) had bacterial infections, while no organisms were identified in 18% cases. Ten babies (11.2%) had COVID-19 and 4 (4.5%) had pertussis. Small for date (n = 15, 55.5%, p < .001) and history of past sick neonatal care unit admission were significantly higher (n = 20, 74.1%, p = .009) in babies with bacterial isolates. Median age of presentation was day 10 (interquartile range [IQR] 8-12). Bacterial ALRTI was more severe with significantly high respiratory score ( p < .001), need for invasive ventilation ( p < .001), systemic complications, and mortality ( p = .012), while viral ALRTI group required longer respiratory support and hospital stay ( p < .001). Conclusions PCR based methods are important in etiological diagnosis of community acquired late onset neonatal pneumonia. Such ALRTI is mostly of viral origin, and this is less likely to be fatal but require longer hospital stay than bacterial pneumonia.