Background: Acute respiratory tract infections are leading cause of mortality in children in India. Further, indiscriminate use of antimicrobials has led to increased drug resistance and large number of adverse drug reactions (ADR). Therefore, aim of study was to study antimicrobial prescribing pattern and record incidence and causality assessment of ADRs in pediatric in-patients having lower respiratory tract infection (LRTI).Methods: In this prospective and observational study total of 300 children aged 2 months to 12 years suffering from LRTI and hospitalized for minimum 48 hrs duration were included. A descriptive analysis was carried out to determine frequency and combinations of antibiotics prescribed and causality and number of ADRs.Results: Out of 300 subjects, 70.3% of patients were males and 54.6% of cases with LRTI belonged to 2-6 months age group. The most frequently prescribed antibiotic was ceftriaxone alone in 67 (22.3%) patients while ceftriaxone and amikacin was the most common 2 drug combination in 60 (20%) patients. Ceftriaxone, ampicillin and gentamicin was most common 3 drug combination in 7 (2.3%) patients. There were 49 cases (16.3%) of ADRs and maximum were in 2-6 months age group and ceftriaxone with amikacin was associated with maximum number 10 (20.4%) of cases. Diarrhoea was most frequent adverse effect associated with antibiotics in 36 (76.6%) cases.Conclusions: The use of cephalosporins (single or combination) are most commonly used drug and associated with maximum number of ADRs in 2-6 months male children with LRTI so clinicians should use them judiciously and rationally.